A. Introduction I1
B. Metric Products I1
C. Metric Facts. I2
_ 1. Length I2
_ 2. Power I2
_ 3. Pressure and Stress I2
D. Applying the Metric System I2
_ 1. Becoming Familiar with the Size of Metric Units I2
_ 2. Units of Length I3
_ 3. Units of Weight I4
_ 4. Units of Volume I5
E. Basic Metric I6
_ 1. Base Units I6
_ 2. Decimal Prefixes I6
_ 3. Plane and Solid Angles I6
_ 4. Derived Units I6
_ 5. Liter, Hectare, and Metric Ton I7
F. Metric Rules I7
_ 1. Rules for Writing Metric Symbols and Names I7
_ 2. Rules for Writing Numbers I8
_ 3. Rules for Conversion and Rounding I8
_ 4. Rules for Linear Measurement (Length) I8
_ 5. Rules for Area I8
_ 6. Rules for Volume and Fluid Capacity I9
G. Conversion Factors for Length, Area, and Volume I9
H. Estimating Basics I10
_ 1. Construction Time/Costs I10
_ 2. Cost I10
_ 3. Design Costs I10
_ 4. Estimating Tools I10
I. Preferred Metric Dimensions in Building Construction I10
J. Construction Trades I11
K. Drawing and Specifications Guidance I13
_ 1. Drawing Scales I13
_ 2. Metric Units Used on Drawings I15
_ 3. Drawing Sizes I15
_ 4. Codes and Standards I16
_ 5. Submittals I16
_ 6. Specifications I17
A. Architectural II1
_ 1. Block II1
_ 2. Brick II1
_ 3. Carpet II2
_ 4. Ceiling Systems II2
_ 5. Drywall II2
_ 6. Doors II2
_ 7. Elevators II3
_ 8. Glass II3
_ 9. Lumber II3
_ 10.Plywood II4
_ 11.Roofing II4
_ 12.Sheet Metal II4
_ 13.Stone II5
_ 14.Metal Studs II5
_ 15.Woodwork II5
B. Civil Engineering II6
_ 1.Units II6
_ 2.Rules for Civil Engineering II6
C. Structural Engineering II8
_ 1. Units II8
_ 2. Rules for Structural Engineers II8
_ 3. Structural Strategies II8
D. Surveying and Project Layout II9
E. Materials Guidance (General) II11
_ 1. Concrete II11
_ 2. Concrete Pipe II11
_ 3. Geotechnical II11
_ 4. Reinforcement II12
_ 5. Pipe II12
_ 6. General Fasteners II13
_ 7. Anchor Bolts II13
_ 8. Fastener Data II14
F. Electrical Engineering II18
_ 1. Units II18
_ 2. Rules for Electrical Engineering II19
_ 3. Conversion Factors II19
_ 4. Conduit II20
_ 5. Cabling II21
_ 6. Fiber Optics II22
_ 7. Lighting Fixtures II22
G. Mechanical Engineering II22
_ 1. Units II22
_ 2. Rules for Mechanical Engineering II23
_ 3. General Guidelines II23
_ 4. Conversion II23
_ 5. Heating, Ventilating, and Air Conditioning II25
_ 6. Pipes II25
_ 7. Schedules II26
_ 8. Temperature II26
Glossary of Terms Appendix 1
Conversion Tables Appendix 2
Project Plans (Illustrative Examples) Appendix 3
Road Design Data . . . . . . . . . . . . . . . 13
Garage Elevation . . . . . . . . . . . . . . . 4
Guardrail . . . . . . . . . . . . . . . . . . . 4
Renovation Plan . . . . . . . . . . . . . . . . 5
Restroom Plan . . . . . . . . . . . . . . . . . 6
Window . . . . . . . . . . . . . . . . . . . . 7
Door Jamb . . . . . . . . . . . . . . . . . . . 8
Foundation Wall . . . . . . . . . . . . . . . . 9
Base Plate . . . . . . . . . . . . . . . . . . 10
Air Distribution . . . . . . . . . . . . . . . 11
Reflected Ceiling . . . . . . . . . . . . . . . 12
A. Introduction. This Handbook introduces the basics of the metric system, including conversion factors from the InchPound System to the System International (SI) Metric System.
1. The Bureau is committed to doing engineering design in the metric system, thereby meeting the requirements of the Metric Conversion Act and Executive Order 12770.
2. Bids to date have not shown detectable premiums for metric. No additional funds are being allocated for metric construction.
B. Metric Products. Some "hard" metric products have minimum order quantities that may limit them to a project involving renovation of an entire floor or more of a building. Most products, however, are identical to the Englishdimensioned products and can be used on any project.
Most modular products are undergoing "hard conversion"  their dimensions will change to new rounded metric numbers. Suspended ceiling grids will convert to 600 x 600 mm or 600 x 1200 mm. Drywall, plywood, and rigid insulation will change to 1200 mm widths, but their thicknesses will remain the same to eliminate the need for recalculating fire and acoustic rates and Uvalues. Raised access flooring will go to 600 x 600 mm. Brick will become 90 x 57 x 190 mm and block will become 190 x 190 x 390 mm; both will use 10mm mortar joints and be laid in 600mm modules. Before specifying hard metric products be sure they are available from the suppliers in the area where the project is located.
What happens to the traditional 2by4 wood stud? Twobyfour inches is a nominal size, not a finished size. Neither wood studs nor other framing lumber will change in crosssection, but they will be spaced at 400 mm instead of 16 inches  about 1/4 inch closer together. Batt insulation installed between studs might not change in width; instead, there will be more of a "friction fit."
There are other products in the same category. A 2inch pipe has neither an inside nor an outside diameter of 2 inches. A 24inch Ibeam contains no actual 24inch dimension. These products won't change sizes either; they'll just be relabeled. Perhaps they will eventually get new nominal names, such as 50mm pipe or 600mm beams. However, with or without names, the metrication process won't be affected.
1. Length. The meter has been defined as the wavelength of a specified radiation equal to 3.2808398 ft. For conversion, one foot equals 0.3048 meters or 304.8 millimeters.
For shorter lengths, the meter is divided into 1000 parts or millimeters (mm); 25.4 mm = 1 inch.
2. Tertiary Powers of 10. Use tertiary powers of 10 (.001, 1, 1000 for units of measure, i.e., millimeters, meters, and kilometers. In most cases, intermediate powers (.01, .1, 100) should not be used in construction, i.e., centimeters, decimeters, and hectometers.
2. Power. In the inchpound system, power is expressed in many different ways  Btu per hour, horsepower, foot/pound force per second, etc. This multitude of terms results in the need for much converting. In the metric system, power consumption, as well as the power output of an electric motor, is expressed in watts, making the efficiency of the motor easily calculated.
For conversion purposes, there are 746 watts in one horsepower.
Problem: A gasoline engine is rated at 100 hp. What is its power output expressed in metric units?
Solution: 100 hp. x (746/hp)W x k/1000 = 74.6 kW
3. Pressure and Stress. In the inchpound system, pressure and stress are expressed in many ways, including pounds per square inch (psi), inches of mercury, and inches of water. In the metric system, the unit for pressure and stress is the pascal. One pascal is defined as the force of one newton exerted over an area of one square meter. In symbolic language, this is shown as Pa = N/m2.
One psi equals 6894 pascals. Since the pascal is such a small unit, pressure and stress are often given in kilopascals (kPa) or megapascals (MPa),
Problem: The operating pressure in a boiler is 125 psi. Express this in pascals with a convenient prefix.
Solution: 125 lb/in2 x 6894 Pa/lb/in2 x k/1000 = 892 kPa
D. Applying the Metric System.
1. Becoming Familiar with the Size of Metric Units. When you hear the terms inch, foot, yard, mile, ounce, pound, pint, quart, and gallon, you have good idea of their size. That's because we use these terms almost every day.
Although we often hear metric terms such as millimeter, centimeter, meter, kilometer, gram, kilogram, and liter, we feel much less comfortable with them because we don't have a good picture of their size. In this section our goal is to provide visual reminders and ball park sizes for these metric units.
A few basic comparisons are worth remembering to help visualize or at least roughly convert between U.S. and metric:
a. One inch is just a fraction (1/64 inch) longer than 25 mm (1 inch = 25.4 mm; 25 mm = 63/64 inch).
b. Four inches are about 1/16 inch longer than 100 mm (4 inches = 101.6 mm; 100 mm = 315/16 inches).
c. One foot is about 3/16 inch longer than 300 mm
(12 inches = 304.8 mm; 300 mm = 1113/16 inches).
d. Four feet are about 3/4 inch longer than 1200 mm
(4 feet = 1219.2 mm; 1200 mm = 3 feet, 111/4 inches).
e. Therefore, the metric equivalent of a 4 by 8 sheet of plywood or drywall would be 1200 x 2400 mm.
f. Rounding down from multiples of 4 inches to multiples of 100 mm makes dimensions exactly 1.6 percent smaller and areas about 3.2 percent smaller.
g. One meter equals about 391/2 inches, just under 31/2 inches longer than a yard.
2. Units of Length. The stem unit of length is the meter. A meter is a little longer than a yard, about a yard plus the length of a piece of chalk.
Illustration 1  Meter (a little longer than a yard).
A millimeter, which is onethousandth of a meter, is about the thickness of a dime.
Illustration 2  Millimeter (about the thickness of a dime).
A kilometer, which is 1000 meters, is about 5/8ths of a mile. If a mile is about 10 city blocks, then a kilometer is about 6 blocks. A mile is 4 times around a typical nonmetric track. A kilometer is about 2.5 times around the track.
Illustration 3  Kilometer (about 5/8 of a mile).
3. Units of Weight. The stem unit of weight is the gram. A gram is quite small. A package of Sweet 'n LowTM has a weight of one gram. A paper clip also has a weight of about one gram.
Illustration 4  Gram (contents of a package of artificial sweetener).
A milligram, which is onethousandth of a gram, is much smaller. Imagine dividing up the contents of a package of artificial sweetener into 1000 equal parts. One of those parts is a milligram.
A kilogram, which is 1000 grams, is a little over 2 pounds (2.2 pounds)  about the weight of a goodsized orange.
4. Units of Volume. The base unit for volume is the liter. A liter is somewhat larger than a quart. A quart is 32 fluid ounces, while a liter is 33.8 fluid ounces, or about a quart and a quarter of a cup.
Illustration 5  Liter (about a quart and a quarter of a cup).
A milliliter, which is onethousandth of a liter, is quite small. It takes about 5 milliliters to make one teaspoon.
1. Base Units. In the metric system, all quantities are derived using decimal units derived from the following base units of measurement, six of which are used in design and construction.
TABLE 1 BASIC UNITS
Quantity/Measurement  S.I. Unit  Symbol 
length mass time electric current temperature luminous intensity  meter kilogram second ampere kelvin candela  m kg s A K cd 
Celsius temperature (oC) is more commonly used than kelvin (K), but both have the same temperature gradients. Celsius temperature is simply 273.15 degrees warmer than kelvin, which begins at absolute zero.
2. Decimal Prefixes. Although prefixes mega (M) for one million (106), giga (G), for one billion (109), micro () for one millionth (106), and nano (n) for one billionth (109) are used in some engineering calculations, the two most commonly used specialized prefixes are below:
TABLE 2 DECIMAL PREFIXES
Prefix  Symbol  Order of Magnitude  Expression 
kilo milli  k m  103 103  1000 (one thousand) 0.001 (one thousandth) 
3. Plane and Solid Angles. The radian (rad) and steradian (sr) denote plane and solid angles. They are used in lighting work and in various engineering calculations. In surveying, the units degree (), minute ('), and second (") continue in use.
4. Derived Units. Other derived units used in engineering calculations are shown below:
TABLE 3 DERIVED UNITS
Quantity  Name  Symbol  Expression 
frequency force pressure, stress energy, work, quantity of heat power, radiant flux electric charge, quantity electric potential capacitance electric resistance electric conductance magnetic flux magnetic flux density inductance luminous flux illuminance  hertz newton pascal joule watt coulomb volt farad ohm siemens weber tesla henry lumen lux  Hz N Pa J W C V F
S Wb T H lm lx  Hz=1/s N=kgm/s2 Pa=N/m2 J=Nm W=J/s C=As V=W/A or J/C F=C/V =V/A S=A/V or 1/ Wb=Vs T=Wb/m2 H=Wb/A lm=cdsr lx=lm/m2 
5. Liter, Hectare, and Metric Ton. The liter (L) measures liquid volume. The hectare (ha) measures surface area. The metric ton (t) is used to denote mass.
1. Rules For Writing Metric Symbols and Names.
a. Print unit symbols in lower case except for liter (L) or unless the unit name is derived from a proper name.
b. Print unit names in lower case, even those derived from a proper name.
c. Leave a space between a numeral and a symbol (write
45 kg or 37 oC, not 45kg or 37oC or 37o C).
d. Do not leave a space between a unit symbol and its decimal prefix (write kg, not k g).
e. Do not use the plural of unit symbols (write 45 kg, not 45 kgs), but do use the plural of written unit names (several kilograms).
f. Do not mix names and symbols (write Nm or newton meter, not Nmeter or newtonm).
g. Do not use a period after a symbol (write "12 g", not "12 g.") except when it occurs at the end of a sentence.
a. Use a zero before the decimal marker for values less than one (write 0.45 g, not .45 g).
b. Use spaces instead of commas to separate blocks of three digits for any number over four digits (write 45 138 kg or 0.004 46 kg or 4371 kg).
3. Rules for Conversion and Rounding.
a. To convert numbers from inchpound to metric, round the metric value to the same number of digits as there were in the inchpound (11 miles at 1.609 km/mi equals 17.699 km, which rounds to 18 km).
b. To avoid mistakes, convert mixed inchpound units (feet and inches, pounds and ounces) to the smaller inchpound unit before converting to metric and rounding (10 feet, 3 inches = 123 inches; 123 inches x 25.4 mm = 3124.2 mm; round to 3120 mm).
c. In a "soft conversion", an inchpound measurement is mathematically converted to its exact (or nearly exact) metric equivalent. With hard conversion, a new rounded, rationalized metric number is created that is convenient to work with and remember. A hard conversion is also an item or component that is made to metric size by a manufacturer.
4. Rules For Linear Measurement (Length).
a. Use only the meter and millimeter in building design and construction.
b. Use the kilometer for long distances and the micrometer for precision measurements.
c. Do not use the centimeter.
d. For survey measurement, use the meter and the kilometer.
a. The square meter is most commonly used.
b. Large areas may be expressed in square kilometers and small areas in square millimeters.
c. The hectare (10 000 square meters) is used for land and water measurement only.
d. Do not use the square centimeter.
e. Linear dimensions such as 40 x 90 mm may be used; if so, indicate width first and length second.
6. Rules For Volume and Fluid Capacity.
a. The cubic meter is most commonly used for volumes in construction and for storage tanks.
b. Use the liter (L) and millimeter (mL) for fluid capacity (liquid volume). One liter is 1/1000 of a cubic meter or 1000 cubic centimeters.
G. Conversion Factors for Length, Area, and Volume. See
Table 4 for guidance when converting from InchPound Units to Metric Units. Appendix 2 contains complete tables of conversion factors.
TABLE 4
QUANTITY  FROM INCHPOUND UNITS  TO METRIC UNITS  MULTIPLY BY: 
Length  mile yard foot foot inch  km m m mm mm  1.609 344 0.914 4 0.304 8 304.8 25.4 
Area  square mile acre acre square yard square foot square inch  km2 m2 ha (10 000 m2) m2 m2 mm2  2.590 99 4046.856 0.404 685 6 0.836 127 36 0.092 903 04 645.16 
Volume  acre foot cubic yard cubic foot cubic foot cubic foot 100 bd feet gallon cubic inch  m3 m3 m3 cm3 L (1000 cm3) m3 L (1000 cm3) mm3  1233.49 0.764 555 0.028 316 8 28 316.85 28.316 85 0.235 974 3.785 41 16 387.064 
NOTE: Underline denotes exact number.
1. Construction Time/Costs. Metric design and construction take the same number of months as English projects. No adjustments have been made to time expectations.
2. Cost. These estimates shall be done in metric units only.
3. Design Costs. There will be no change to the standard design fee charts used to calculate design costs, given that: a. specifications are metric,
b. metric estimating tools are offered,
c. criteria are metric,
d. most codes and standards are in metric, and
e. sample drawings exist for most items.
4. Estimating Tools. The R.S. Means Company, Inc. offers metric estimating handbooks. There are several construction metric databases available from private firms.
I. Preferred Metric Dimensions in Building Construction.
1. In design and construction, most measurement statements involve linear measurement. Frequently, such measurement statements are not independent; they are part of a set or sequence of values. A common set of preferred dimensions is used to establish the geometry of a building as well as the sizes of constituent components or assemblies. To select the most appropriate metric values during conversion of linear dimensions, it is helpful to appreciate the concept of dimensional coordination, which involves special dimensional preferences for buildings and building products. Because all preferred dimensions are related to a building module, the term modular coordination is sometimes substituted. In building construction, the fundamental unit of size is the basic module of 100 mm. It is slightly shorter than the 4" (101.6 mm) module that has been used in the United States, and should not be equated with this customary module because metric modular product dimensions will be 1.6% shorter.
2. The basic module of 100 mm has already been endorsed as the basic unit of size in metric dimensional coordination in the United States. Preferred dimensions of buildings and preferred sizes of building components should be whole multiples of 100 mm, wherever practicable.
3. Building products vary from small components placed by hand that range in size up to about 1000 mm, to larger elements placed by mechanical means that may range up to 12 000 mm.
Building dimensions vary from small thicknesses of structural elements and dimensions of small spaces to very large spaces with dimensions of 60 000 mm or more in special structures. To ensure efficient use of materials, preferred dimensions play an important part in design, production, and construction.
4. It is important to appreciate that preferred dimensions in the context of metric dimensional coordination are reference dimensions or ideal dimensions rather than actual dimensions. Allowances for joints, tolerances, and deviations are taken into account in the determination of actual dimensions. For example, when a component is described by a preferred size of 400 mm, this dimension includes an allowance for half a joint width on either side of the component, and the actual dimension is less to ensure fit in a coordinating space. If the design joint thickness is 10 mm, the dimension for use as a manufacturing target dimension will be 390 mm.
5. The construction process involves joining many individual and often repetitive components, assemblies, or elements into an organized whole. Therefore, building dimensions that are highly divisible multiples of the basic module are superior to prime number multiples.
J. Construction Trades. The metric units used in the construction trades are charted below. The term "length" includes all linear measurements (that is, length, width, height, thickness, diameter, and circumference).
TABLE 5  
TRADE  QUANTITY  UNIT  SYMBOL 
Carpentry  length  meter, millimeter  m, mm 
Concrete  length  meter, millimeter  m, mm 
area  square meter  m2  
volume  cubic meter  m3  
temperature  degree Celsius  oC  
water capacity  liter (1000 cm3)  L  
mass (weight)  gram, kilogram  g, kg  
crosssec. area  square millimeter  mm2  
Drainage  length  meter, millimeter  m, mm 
area  square meter  m2  
volume  cubic meter  m3  
slope  millimeter/meter  mm/m  
Electrical  length  meter, millimeter  m, mm 
frequency  hertz  Hz  
power  watt, kilowatt  W, kW  
elec. current  ampere  A  
elec. potential  volt, kilovolt  V, kV  
resistance  ohm  
energy  kilojoule, megajoule  kJ, MJ  
Excavating  length  meter, millimeter  m, mm 
volume  cubic meter  m3  
Glazing  length  meter, millimeter  m, mm 
area  square meter  m2  
HVAC  length  meter, millimeter  m, mm 
force  newton, kilonewton  N, kN  
volume  cubic meter  m3  
temperature  degree Celsius  oC  
capacity  liter (1000 cm3)  L  
velocity  meter/second  m/s  
rate of heat flow  watt, kilowatt  W, kW  
energy, work  kilojoule, megajoule  kJ, MJ  
Masonry  length  meter, millimeter  m, mm 
area  square meter  m2  
mortar volume  cubic meter  m3  
Painting  length  meter, millimeter  m, mm 
area  square meter  m2  
capacity  liter, milliliter(cm3)  L, mL  
Paving  length  meter, millimeter  m, mm 
area  square meter  m2  
Plastering  length  meter, millimeter  m, mm 
area  square meter  m2  
water capacity  liter (1000 cm3)  L  
Plumbing  length  meter, millimeter  m, mm 
mass  gram, kilogram  g, kg  
capacity  liter (1000 cm3)  L  
pressure  kilopascal  kPa  
Roofing  length  meter, millimeter  m, mm 
area  square meter  m2  
slope  millimeter/meter  mm/m  
Steel  length  meter, millimeter  m, mm 
mass  gram, kilogram metric ton (1000 kg)  m2 t  
Surveying  length  meter, kilometer  m, km 
area  square meter square kilometer hectare (10,000 m2)  m2 km2 ha  
plane angle  degree (nonmetric) minute (nonmetric) second (nonmetric)  o ' "  
Trucking  distance  kilometer  km 
volume  cubic meter  m3  
mass  metric ton (1000 kg)  t 
K. Drawing and Specifications Guidance.
a. Metric drawing scales are expressed in nondimensional ratios.
b. Nine scales are preferred; 1:1 (full size), 1:5, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, and 1:1000. Three others have limited usage: 1:2, 1:25, and 1:250.
TABLE 6  
InchFoot Scales  Ratios  Metric Scales  Remarks  
Preferred  Other  
Full Size  1:1  1:1  No Change  
Half Size  1:2  1:2  No Change  
4" = 1'0" 3" = 1'0"  1:3 1:4 
1:5 
Close to 3" scale  
2" = 1'0" 11/2" = 1'0"
1" = 1'0"  1:6 1:8
1:12 
1:10 
Between 1" and 11/2" scales  
3/4" = 1'0"
1/2" = 1'0"  1:16
1:24  1:20 
1:25  Between 1/2" and 3/4" scales Close to 1/2" scale 
3/8" = 1'0" 1/4" = 1'0"
1" = 5'0" 3/16" = 1'0"  1:32 1:48
1:60 1:64 
1:50 
Close to 1/4" scale  
1/8" = 1'0"
1" = 10'0" 3/32" = 1'0"  1:96
1:120 1:128  1:100  Close to 1/8" scale  
1/16" = 1'0"  1:192  1:200  Close to 1/16" scale  
1" = 20'0"  1:240  1:250  Close to 1" = 20'0" scale  
1" = 30'0" 1/32" = 1'0" 1" = 40'0"  1:360 1:384 1:480 
1:500 
Close to 1" = 40'0"  
1" = 50'0" 1" = 60'0" 1" = 1 chain 1" = 80'0"  1:600 1:720 1:792 1:960 
1:1000 
Close to 1" = 80'0" 
2. Metric Units Used on Drawings.
a. Use only one unit of measure on a drawing. Except for largescale site or cartographic drawings, the unit should be the millimeter (mm). Centimeters shall not be used. On large scale site or cartographic drawings, the unit should be the meter.
b. Metric drawings use millimeters (mm) exclusively. Each drawing should have the following note on it:
c. Metric drawings should almost never show decimal millimeters (for example: 2034.5), unless a high precision part or product thickness is being detailed. Use whole millimeters (for example: 2035).
d. Dual dimensions should not be used; for example, 200 mm (77/8").
e. A space should separate groups of three digits on drawing dimensions. This allows faster and more accurate dimensional interpretation. For example: A 20meter dimension would show as 20 000 (twenty thousand millimeters).
a. The ISO "A" series drawing sizes are preferred metric sizes for design drawings. A0 is the base drawing size with an area of one square meter. Smaller sizes are obtained by halving the long dimension of the previous size. All A0 sizes have a heighttowidth ratio of one to the square root of 2 (1:1.414).
b. There are five "A" series sizes:
(1) A0 1189 x 841 mm (46.8 x 33.1 inches)
(2) A1 841 x 594 mm (33.1 x 23.4 inches)
(3) A2 594 x 420 mm (23.4 x 16.5 inches)
(4) A3 420 x 297 mm (16.5 x 11.7 inches)
(5) A4 297 x 210 mm (11.7 x 8.3 inches)
4. Codes and Standards. Codes and standards needed for design are available today in metric. Codes and standards have not hindered renovation or new construction designs in metric to date. For codes or standards not in metric, rounding techniques have proven sufficient.
5. Submittals. To assist manufacturers with metric conversion, the following submittal classes should be utilized. These classes should be supplemented for each project.
a. Class 1. Drawings That Must Be Metric Only. English units are not permitted on these submittals. Drawings must use metric scales. In general, any drawing that is job specific, and is custom generated for this project, must be in metric only. Here are some samples:
Floor Plans
Reflected Ceiling Drawings
Stairwell Erection Drawings
Foundation Wall Drawings
Concrete/Rebar Installation Drawings
Sitework Drawings
Sheeting and Shoring Plans
Steel Erection/Fabrication Drawings and Details
Precast Manhole Drawings
Door Schedules
Wall Paneling Drawings
Caisson Details
Millwork Drawings
Cabinet Work Details
Toilet Room Details
Ductwork Drawings
Pipe Installation Drawings
HVAC Schedules
Switchgear Drawings
Electrical Component Layout Drawings
Signage Drawings
b. Class 2. Data That Must Be Metric Only. The following types of items must be submitted in metric only. Data generated specifically for these projects must also be submitted in SI only.
Concrete Design Mixes
Concrete Test Data
Core Bore Depths Data
Aggregate Mixes (must show metric sieves)
Mechanical Air and Water Flow or Balancing Data
Environmental or Hazardous Material Data
Most Test Data
Other data generated for the project that is not in bound, preprinted catalogs or publications.
a. Millimeters (mm). Metric specifications should use mm for most measurements, even large ones. Use of mm is consistent with dimensions in major codes, such as the National Building Code (Building Officials and Code Administrators International, Inc.) and the National Electric Code (National Fire Protection Association).
Use of mm leads to integers for all building dimensions and nearly all building product dimensions, so use of the decimal point is almost completely eliminated.
b. Meters (m). Meters may be used where large, round metric sizes are involved.
Example: "Contractor will be provided an area of 5 by 20 meters for storage of materials."
c. Centimeters (cm). Centimeters should never be used in specifications. Centimeters are not used in major codes. Use of centimeters leads to extensive usage of decimal points. Whole millimeters should be used for specific measurements, unless extreme precision is being indicated. A credit card is about 1 mm thick.
(1) Example 1  Mortar Joint Thickness. If a 3/8inch mortar joint between brick is needed, this would convert to 9.525 mm. Whole mm should be used, so specify 10 mm joint thickness.
(2) Example 2  Stainless Steel Thickness. Bath accessories are commonly made from 22gauge (0.034in) thick stainless steel. Exact conversion is 0.8636 mm. This is a precision measurement; an appropriate conversion is 0.86 mm.
(3) Example 3  Concrete Thickness. Concrete shall be 200 mm thick.
(4) Example 4  Clearance. Clearance shall be 1500 mm.
In specifications, the unit symbols (e.g., m or mm) are almost always present. Little room exists for confusion. On drawings, using mm eliminates the need to write m or mm and eliminates decimal usage for all but largescale civil and road design drawings.
A small class of items reference standards using centimeters or square centimeters, such as fire ratings for some products. These items only, which account for less than 2 percent of specification references, should make reference to centimeters or square centimeters.
d. Nominal Technique. Many specification references can effectively use nominal mass, nominal volume, or nominal length technique. For example, if one gallon (3.785 L) of product X is required, the specification could be rewritten using nominal volume, requiring 4 L ( 0.25 L). Users can then say "4 liters" when referencing this item, while still allowing the current product to be submitted.
e. Professional Rounding. This technique takes the result of simple mathematical rounding and applies professional judgment. First, a small discussion of metric design is necessary. The basic module of metric design is 100 mm. The multimodules and submodules, in preferred order, are 6000, 3000, 1200, 600, 300, 100, 50, 25, 20, and 10.
(1) How to Use Professional Rounding.
(a) Convert the dimension mathematically. Let's say a pavement width in some codes becomes 914 mm minimum.
(b) Select a replacement dimension.
(i) 1000 would be the preferred replacement.
(ii) 950 would be used only with justification.
(iii) 900 would offend the code and could not be used.
(2) How to Correctly Apply Professional Judgment to Design Criteria.
(a) Example: Conversion of an Existing Code Requirement
(i) Determine the nonoffending direction. National Building Code Article 1011.3 requires 44 inches (1118 mm) of unobstructed pedestrian corridor width. However, 1118 mm is not a clean number. It should be rounded to facilitate the cleanest construction possible. Narrower offends the code. The nonoffending direction is larger, so it is better to round up.
(ii) Every effort should be made to keep design dimensions in increments of 100 mm, which is the basic module, or in multimodules.
f. Measurements. All measurements in construction specifications should be stated in metric. Until existing specification systems are fully converted, the specifier may:
(1) Specify metric products. Check to see if the products to be specified are available in metric sizes.
(2) Refer to metric or dual unit codes and standards. The American Society of Heating, Refrigerating, and AirConditioning Engineers, Inc. (ASHRAE), American Society of Mechanical Engineers (ASME), and American Concrete Institute (ACI), among others, publish metric editions of some standards. The Building Officials and Code Administrators (BOCA), as well as the American Society for Testing and Materials (ASTM) and the National Fire Protection Association (NFPA), publish their documents with dual units (both metric and inchpound measurements). In addition, most handicapped accessibility standards and a number of product standards are published with dual units. The metric measurements are virtually exact, soft numerical conversions that, over time, will be changed through the consensus process into rounded hard metric dimensions. For now, use the soft metric equivalents.
(3) Convert existing unit measurements to metric. Follow the conversion rules below.
g. Standards, Criteria, and Product Information. For organizations that publish construction standards, criteria, or product information: Review all active documents and follow the conversion rules below. The standards referenced in e. and f. below may be consulted for additional guidance conversion.
(1) Whenever possible, convert measurements to rounded, hard metric numbers. For instance, if anchor bolts are to be imbedded to a depth of 10 inches, the exact converted length of 254 mm might be rounded to either 250 mm (9.84 inches) or 260 mm (10.24 inches). The less critical the number, the more rounded it can be, but ensure that allowable tolerances or safety factors are not exceeded. When in doubt, stick with the exact soft conversion.
(2) Round to "preferred" metric numbers.
(a) The preferred numbers for the "1 foot = 12 inches" system are, in order of preference, those divisible by 12, 6, 4, 3, and 2.
(b) Preferred metric numbers are, in order, those divisible by 10, 5, and 2, or decimal multiples thereof. National Bureau of Standards (NBS) Technical Note 990, The Selection of Preferred Metric Values for Design and Construction, explains the concept of preferred numbers in detail and states in its foreword:
It is widely recognized that a transfer to a metric technical environment based upon a soft conversion  that is, no change other than the description of the physical quantities and measurements in metric units  would cause considerable longer term problems and disadvantages due to the encumbrance of the resulting awkward numbers. The overall costs of soft conversion could greatly outweigh any savings due to its short term expediency.
The Technical Note provides a rational basis for the evaluation and selection of preferred numerical values associated with metric quantities. Precedent has shown that the change to metric units can be accompanied by a change to preferred values at little or no extra cost, especially in specifications, codes, standards, and other technical data.NBS Technical Note 990; The Selection of Preferred Metric Values for Design and Construction
(3) Use hand calculators or software conversion programs that convert inchpounds to metric. They are readily available and are indispensable to the conversion process. Simply check with any store or catalog source that sells calculators or software.
(4) Be careful with the decimal marker when converting areas and volumes; metric numbers can be significantly larger than inchpound numbers (a cubic meter, for instance, is one billion cubic millimeters).
(5) Use ASTM E621, Standard Practice For the Use of Metric (SI) Units in Building Design and Construction, as a basic reference.
(6) Follow the rules for usage, conversion, and rounding in ASTM E 380, Standard Practice of Use of the International System of Units (SI), Sections 3 and 4; or American National Standards Institute (ANSI) 268, Metric Practice, Sections 3.5 and 4.
a. Standard sizes are 90, 140, and 190 mm thick, with a 190 x 390 mm face. Normal metric modular block is 190 x 190 x 390 mm. This nearly equates to 71/2 x 71/2 x 153/8 inches. American modular block is 194 x 194 x 397 mm, quite similar to metric block. Stacking nonmortar joint block is usually 203 x 203 x 406 mm. Hard metric block has 12.5 blocks per m2.
b. Metric block has been installed on U.S. projects. Some metric blocks are being supplied using molds borrowed from sources that already owned them, eliminating mold purchase costs.
c. The standard mortar joint for block is 10 mm.
a. The "metric modular brick" is the most common. Its size is 90 x 57 x 190 mm (39/16 x 21/4 x 71/2 inches). Jumbo brick is 90 x 90 x 190 mm.
b. American modular brick is:
(1) 35/8 x 21/4 x 7 5/8 inches (92 x 57 x 194 mm) when a 3/8inch joint is used.
(2) 31/2 x 23/16 x 71/2 inches (89 x 56 x 190 mm) when a 1/2 inch joint is used.
c. Thus the standard American modular brick used with a 1/2inch joint is so close to the metric modular brick that it can be used with only a slight variation in joint thickness during field installation.
d. Three vertical courses of metric modular brick with 10 mm joints equals 201 mm, which is rounded to 200. Two jumbo courses equals 200. Weepholes are mostly spaced in 100 mm sizes. (e.g., 600 mm). Seventyfive modular metric bricks per m2, 50 metric jumbo bricks per m2.
e. Metric brick has been used on U.S. projects. Standard mortar joint for brick and block is 10 mm. Brick should be specified in metric, regardless of whether ASTM C 216 or ASTM C 62/AASHTO M 114 is used.
a. Most firms have the dies and can or do make metric carpet tile. Most common sizes are 500 x 500 mm and 600 x 600 mm.
b. Minimum orders are available (several hundred square meters or less). As the industry goes metric, premiums for minimums will shrink or be eliminated.
a. Many domestic manufacturers regularly make hard metric tiles and grids for use in metric projects. Most common sizes are 600 x 600 mm and 600 x 1200 mm.
b. Many design and construction projects, both renovation and new construction, are using the 600 x 600 mm system.
c. Many facilities with 2 x 2 grids are not adversely affected by use of new 600 x 600 mm grids.
d. With hard metric ceilings, room dimensions can be multiples of 600 mm, giving clean, rounded dimensions to construction personnel for layout.
a. Only sheet length and width are classified in hard metric. The standard sheet width is 1200 mm. Lengths available are 2400 mm and several longer sizes.
b. Thicknesses remain the same to minimize code impact. Most architects show these as 13 x 16 mm on drawings, instead of the exact 12.7 and 15.9 mm. Standard stud spacing is 400 mm, as it is the closest to 16 inches and is an even multiple of the sheet size.
a. A common metric door size is 900 x 2100 mm, although 1000 x 2000 mm is sometimes used. This may be used on metric projects where other project specific design criteria are satisfied.
b. Louvers and glass should be in hard metric dimensions, such as 300 x 300 mm, 450 x 450 mm, etc.
c. Door thicknesses will remain the same, being identified by the nominal mm equivalent. Most architects softconvert door thickness and are using nominal 45 mm as standard.
d. Most door frame section dimensions are being rounded to the nearest 1 mm (e.g., 13, 25, 41, 50, or 80 mm). Lengths and widths match hard metric door sizes and should be hard metric. (e.g., 900 x 2100 mm)
a. Capacities should be specified to the next lowest 50 kg. (e.g., 40,000 lb = 18 144 kg). Signage in the elevator would show 18 100 kg only.
b. Most manufacturers can make hard metric platforms. Specifying 50 mm platform sizes is preferred, but allow standard English platform sizes to be submitted. (For example, 5'7" x 7' platform = 1702 x 2134 mm. Specify as 1700 x 2100 mm, but approve the standard English size) Note: Code and criteria requirements may restrict this approach and must be considered on each project.
c. Speeds should be in meters/second, shown to two digits (e.g., 0.64 m/s, 0.51 m/s).
d. Thus, manufacturers supply standard product, and rounded numbers appear in specifications and drawings as well as to the public.
a. ASTM C 1036 gives metric sizes for flat glass, heat absorbing glass, and wired glass.
b. Glass shall be specified in mm only.
c. Thicknesses for Type 1, Transparent Flat Glass are 1, 1.5, 2, 2.5, 2.7, 3, 4, 5, 5.5, 6, 8, 10, 12, 16, 19, 22, 25, and 32.
a. Two by fourinch is a nominal size. Neither wood studs nor other framing lumber will change in crosssection. A 2 x 4inch piece can be soft converted to 51 x 102 mm (nominal) or 38 x 89 mm actual. The actual dimensions in millimeters would most commonly be used.
b. Millimeter dimensions are frequently used in exact layout work only, such as layout of cabinetry, but 2 x 6 and
2 x 10 boards will still be used.
a. Projects using plywood should specify metric sheets.
b. Thickness is the same to minimize production impacts. The standards are 12.7 and 19.05 mm, commonly given nominal thicknesses on drawings (e.g., 19 mm).
a. Use millimeters squared for areas.
b. State membrane thickness in millimeters only.
c. Lap widths should be even millimeters. (e.g., 100 mm, 150 mm, etc.)
a. Most specification references use gauge numbers followed by the decimal inch thickness.
b. Metric specifications use millimeter thickness. It is not the intent to change the thickness of currently used sheeting. The thickness under "Specify" is thinner than the actual gauge thickness, since specifications give minimum thickness.
The following chart may be used to specify sheet metal:
Gauge  Inch  Exact mm  Specify (< exact) mm  % Thinner 
32  0.0134  0.3404  0.34  0.1 
30  0.0157  0.3988  0.39  2.2 
28  0.0187  0.4750  0.47  1.1

26  0.0217  0.5512  0.55  0.2 
24  0.0276  0.7010  0.70  0.1 
22  0.0336  0.8534  0.85  0.4

20  0.0396  1.0058  1.00  0.6 
18  0.0516  1.3106  1.30  0.8 
16  0.0635  1.6129  1.60  0.8

14  0.0785  1.9939  1.90  4.7 
12  0.1084  2.7534  2.70  1.9 
10  0.1382  3.5103  3.50  0.3

8  0.1681  4.2697  4.20  1.6 
This schedule was developed since no existing material was found to clearly identify existing sheeting in metric units. Until a more efficient method is developed to address this issue, specifiers may wish to retain the gauge number in specifications, coupling this with a rounded mm size.
c. For example: Provide grab bar with a minimum wall thickness of 18 gauge (0.051 inch) should be replaced with: Provide grab bar with minimum wall thickness of 1.3 mm. Since 18 gauge is thicker than 1.3 mm, 18 gauge is acceptable.
d. Show minimum thickness in millimeters only. Specifying 1 or 0.1 mm thicknesses wherever possible. (e.g., 1 mm, 1.6 mm). Hard metric sheet metal is obtainable, even in smaller quantities.
13. Stone. Stone, such as granite and marble, should be specified in hard metric (e.g., 30 or 50 mm thick, or 100 x 300).
14. Metal Studs. Common metal studs are available in the following nominal mm sizes, which closely align with the dimensions in the standard English sizes: 42, 64, 92, 102, and 153 mm. A 22 mm hat channel for furring is also common. both wood and metal studs are soft converted and will not change in actual cross section.
15. Woodwork. Custom casework, such as cabinets, builtin benches, shelves, security desks, and judges benches, should be developed in hard metric to the fullest degree possible.
a. Cabinets. Many cabinet widths are shown as increments of 50 mm. (e.g., 450, 500 mm wide).
b. Lockers. Dimensions should be furnished in metric sizes.
1. Units. The metric units used in civil and structural engineering are:
a. meter (m)
b. kilogram (kg)
c. second (s)
d. newton (N)
e. pascal (Pa)
2. Rules for Civil Engineering.
a. There are separate units for mass and force.
b. The kilogram (kg) is the base unit for mass, which is the unit quantity of matter independent of gravity.
c. The newton (N) is the derived unit for force (mass times acceleration, or kgm/s2). It replaces the unit "kilogramforce" (kgf), which should not be used.
d. The newton meter designates torque, not the joule.
e. The pascal (Pa) measures pressure and stress (Pa=N/m2).
f. Structural calculations should be shown in MPa or kPa (megapascals or kilopascals).
g. Plane angles in surveying (cartography) will continue to be measured in degrees (either decimal degrees or degrees, minutes, and seconds) rather than the metric radian.
h. Percentages should be used primarily for long, standing slopes, while ratios should generally be used for shorter or steeper distances. Since both are basically "dimensionless"that is, they refer to each other instead of a specific standard of measurementeither could be used as required. Just remember to follow current, standard designating practices regarding each.
When using percentages, follow this rule: Percent x 10 = mm/m (vertical distance in millimeters per horizontal meter) For example: 2% x 10 = 20 mm/m, and 45% = 450 mm/m.
i. Road construction must be designed using metric units. For additional guidance, use the AASHTO Guide to Metric Conversion for geometric design values, lane and shoulder widths, curb heights, sight distances, curvatures, and other values.
TABLE 8
Quantity  From InchPound Units  To Metric Units  Multiply by 
Mass  lb kip  kg metric ton  0.453 592 0.453 592 
Mass/unit length  plf  kg/m  1.488 16 
Mass/unit area  pcf  kg/m2  1.482 43 
Mass density  pcf  kg/m3  16.018 5 
Force  lb kip  N kN  4.448 22 4.448 22 
Force/unit length  plf klf  N/m kN/m  14.593 9 14.593 9 
Pressure, stress, modulus of elasticity  psf ksf psi ksi  Pa kPa kPa MPa  47.880 3 47.880 3 6.894 76 6.894 76 
Bending moment, torque, moment of force  ftlb ftkip  Nm kNm  1.355 82 1.355 82 
Moment of mass  lbft  kgm  0.138 255 
Moment of inertia  lbft2  kgm2  0.042 140 1 
Second moment of area  in4  mm4  416 231 
Section modulus  in3  mm3  16 387.064 
NOTE: Underline denotes exact number.
kip = 1000 lb
metric ton = 1000 kg
1. Units. The metric units used in structural engineering are:
a. meter (m)
b. kilogram (kg)
c. second (s)
d. newton (N)
e. pascal (Pa)
2. Rules for Structural Engineering.
a. There are separate units for mass and force.
b. The kilogram (kg) is the base unit for mass, which is the unit quantity of matter independent of gravity.
c. The newton (N) is the derived unit for force (mass times acceleration, or kgm/s2). It replaces the unit "kilogramforce" (kgf), which should not be used.
d. The newton meter designates torque, not the joule.
e. The pascal (Pa) measures pressure and stress (Pa=N/m2).
f. Structural calculations should be shown in MPa or kPa (megapascals or kilopascals).
g. Design dimensions must be rounded. Bar spacing, wall and slab thickness, and similar dimensions must be even mm
(e.g., 100, 250, or 400 mm), not exact conversions (e.g., 305 mm).
h. Structural steel shall be specified in metric only, such as 250 MPa. Shapes shall be specified according to the millimeter sizes and dimensions in ASTM A 6M.
i. Wind pressures are given in Pa, while wind speeds are most frequently given in m/s.
a. Fasteners. Use ASTM A 325M and A 490M metric bolts. There are seven standard metric bolt sizes, which replace the nine bolts currently used. Standard sizes are 16, 20, 22, 24, 27, 30, and 36 mm.
b. Steel.
(1) ASTM A 6/A 6M lists both inch and mm dimensions of the shapes.
(2) Another reference is the International Standards Organization (ISO) standard for steel.
c. Floorload.
(1) Calculations are in kPa, but floorloading can be in kilograms (kg) per square meter because many dead and live loads are given in kg. Use the following rounded, slightly conservative, rule: kPa x 100 = kg/m2 (e.g., 5 kPa x 100 = 500 kg/m2)
(2) The chart below gives kPa strength ratings that can be used to replace the psf strength rating.
Previous (psf)  New (kPa)  Percent Stronger 
50  2.5  4.4 
80  4  1.8 
100  5  4.4 
120  6  4.4 
150  7.5  4.4 
200  10  4.4 
250  12  0.2 
300  15  4.4 
350  17  1.4 
400  20  4.4 
450  22  2.1 
500  24  0.2 
1 kPa components. Drawings and calculations should reflect these numbers only.
(4) In existing facilities, the preferred method is to convert values to exact kPa and then round to the next lowest 0.1 kPa.
D. Surveying and Project Layout.
1. Databases of hundreds of thousands of horizontal and vertical survey control points on which U.S. surveys are based have been completely metric since 1983. USGS, which produces topographic maps of terrain elevations, has digitally mapped the U.S. surface. The ground distance between each pair of digitized points is 30 meters. Thus, survey and mapping data needed to do metric design and construction in the United States is available.
2. The following information can be used as guidance on how site plans and topographic maps are to be executed:
a. Contour intervals utilize either 1000, 500, or 250 mm as contour intervals, depending on site slope.
b. Elevation measurements are given in mm.
c. Benchmark elevations are converted from feet to mm.
3. Examples:
a. Benchmark is 314.15 feet. Convert to 95 753
b. Sample Finished Floor Elevation: 105 025
c. Sample Top of Curb: TC 305 224
d. Sample Bottom of Curb: BC 305 024
e. Sample Contour Lines:
106 000
105 500
4. Large mapping scales use metric symbols. 1:2000 is written as 1:2k, 1:5,000,000,, as 1:5M. Contour lines may also be given in meters.
5. Electronic surveying and mapping equipment provides data in metric squared units. Many states utilize electronic data measurement (EDM) equipment, which almost always can work in metric units.
6. Plane angles in surveying (cartography) will continue to be measured in degrees (either decimal degrees or degrees, minutes, and seconds) rather than the metric radian.
7. Percentages should be used primarily for long, standing slopes, while ratios should generally be used for shorter or steeper distances. Since both are basically dimensionless that is, they refer to each other instead of a specific standard of measurementeither could be used as required. Just remember to follow current, standard designating practices regarding each. When using percentages, follow this rule: Percent x 10 = mm/m (vertical distance in millimeters per horizontal meter) For example: 2% x 10 = 20 m/m, and 45% = 450 mm/m.
E. Materials Guidance (General).
a. Concrete strength is specified throughout the country in MPa. The following strengths should be used in metric construction. The general purpose concrete strengths are reduced from 6 strengths to 4 strengths. Strengths above 35 MPa should be specified in 5 MPa intervals (40, 45, 50, 55, etc.).
Previous psi  Exact Conversion MPa  Specify MPa 
2 500 3 000 3 500 4 000 4 500 5 000  17.23 20.67 24.12 27.56 31.01 34.45  20 20 or 25* 25 30 35 35 
b. ACI 318M, metric version, should now be used.
c. Slump Limits on metric projects always use 10 or 5 mm increments (e.g., 75, 80, or 90 mm).
a. ACPA 5.0 states that concrete pipe can now be specified using hard metric ASTM and AASHTO standards.
b. Reinforced concrete pipe (RCP) is specified as ASTM
C 76M/AASHTO M 170M.
c. ASTM C76 RCP meets the hard metric standard, since tolerances were set in the hard metric standard to accept current product.
d. For nonreinforced concrete pipe, sizes are as follows:
C 76M sizes (mm)  300  375  450  525  675  750  825  900  1050 
1200  1350  1500  1650  1800  1950  2100  2250  2400
 
C 14M sizes  100  150  200  250  300  375  450  525  600 
675  750  825  900 
a. Metric projects will use ASTM A 615M reinforcing bars for general purpose applications. The A 615M reinforcing bar comes in Grades 300 and 400, indicating 300 and 400 MPa yield strength.
b.There are 8 bar sizes, which replace the 11 bar sizes currently used, as listed below:
Size  Diam (mm)  Area (mm2)  Size  Diam (mm)  Area (mm2) 
3 4 5  9.52 12.70 15.87  71 129 200  10M 15M 20M  11.3 16.0 19.5  100 200 300 
6 7 8  19.05 22.22 25.40  284 387 510  25M 30M 35M  25.2 29.9 35.7  500 700 1000 
9 10 11  28.65 32.25 35.81  645 819 1006  45M 55M  43.7 56.4  1500 2500 
14 18  43.00 57.32  1452 2581 
c. Some applications may need A 616M, A 617M, A 706M, or
A 775M. Note that a nominal 15 mm bar is called a "Number 15 bar."
5. Pipe. Steel pipe and copper tube sizes will not now change, since American sizes are still used in many parts of the world. Designate tube sizes by nominal mm size. Hard metric pipe sizing may be used in the future. ASTM B 88M provides standard hard metric copper tube sizes. During the transition to metric units, the following paragraph and chart should be placed on the mechanical cover sheet:
"ALL SIZES ARE INDUSTRYSTANDARD ASTM A 53 PIPE AND ASME B 88 TUBE DESIGNATED BY THEIR NOMINAL MILLIMETER (mm) DIAMETER EQUIVALENT. SEE CHART BELOW."
Nominal Size  
Inch  mm 
1/2  15 
3/4  20 
1  25 
11/4  32 
11/2  40 
2  50 
21/2  65 
3  80 
31/2  90 
4  100 
5  125 
6  150 
a. U.S. industry is now using metric fasteners extensively.
b. The Thomas Register lists hundreds of firms under Metric Fasteners, Metric Screws, and Metric Bolts. The Industrial Fasteners Institute (IFI) has guides for fastener types and producers.
c. Many pieces of mechanical and electrical equipment already use both metric and English fasteners. Metric fasteners use M numbers. (For example, M10 x 40 is a nominal 10 mm diameter and 40 mm length.)
d. Metric socket head cap screws, set screws, hex bolts, and similar items are available.
7. Anchor Bolts. Metric anchor bolts (e.g., L, J and U bolts) are available. ASTM F 568 gives metric chemical and mechanical data for carbon steel anchor bolts and studs, and also references ANSI dimensional standards.
a. ISO Metric Grades. As given in ISO 898 and ASTM F 568, ISO metric grades should be used. Many anchor bolts are made from low carbon steel grades, such as ISO classes 4.6, 4.8, and 5.8.
b. Preferred Diameters. Preferred nominal diameters for items such as anchor bolts and threaded rod are as shown below. Reference individual standards prior to specification. Sizes are given between M5 and M45, as these are commonly used in construction.
1: M5 6 8 10 12 16 20 24 30 36 42
2: M14 18 22 27 33 39 45
3: M45 7 9 11 15 17 25 26 28 32 35 38 40
8. Fastener Data. Tables 9 and 10 provide much of the data available for different metric fasteners.
TABLE 9  
Basic Product  Product Type and Head Style  Size Range  For Dimensions Refer to:
 For Mechanical and/or
Performance
Properties
Refer To:

Metric Bolts  hex  M5M100  ANSI/ASME B18.2.3.5M 
ASTM F #568
ASTM F#486M
ASTM F #738 
heavy hex  M12M36  ANSI/ASME B18.2.3.6M  
round head short square neck (carriage)  M8M20  ANSI/ASME B18.5.2.1M  
round head square neck (carriage)  M5M24  ANSI/ASME B18.5.2.2M  
bent  M5 and larger  IFI 528  
heavy hex structural  M12M36  ANSI/ASME B18.2.3.7M  ASTM A#325M ASTM A#490M  
hex transmission tower  M16M24  IFI 541  IFI 541  
Metric Screws  hex cap  M5M100  ANSI/ASME B18.2.3.1M  ASTM F#568
ASTM F#468M
ASTM F#738 
formed hex  M5M24  ANSI/ASME B18.2.3.2M  
heavy hex  M12M36  ANSI/ASME B18.2.3.3M  
hex flange  M5M16  ANSI/ASME B18.2.3.4M  
heavy hex flange  M10M20  ANSI/ASME B18.2.3.9M  
hex lag  524mm  ANSI/ASME B18.2.3.8M  see note 3  
Metric Studs  double end  M5M100  IFI 528  ASTM F#568 ASTM F#468M ASTM F#736 
continuous thread  M5M100  
Metric Locking Screws  prevailing torque, nonmetallic insert  M1.6M36  see note 3  IFI 524 
chemical coated  M6M20  see note 3  IFI 525  
Metric Socket Screws  socket head cap  M1.6M48  ANSI/ASME B 18.3.1M  ASTM A#574M F#837M 
socket head shoulder  6.525mm  ANSI/ASME B 18.3.3M  ASTM F#835M
ASTM A#574M
ASTM F#879M  
socket button head cap  M3M16  ANSI/ASME B18.3.4M  
socket countersunk head cap  M3M20  ANSI/ASME B18.3.5M  
socket set  1.624mm  ANSI/ASME B18.3.6M  ANSI/ASME B.18.3.6M ASTM F#912M ASTM F#880M  
Metric Nuts  hex, style 1  M1.6M36  ANSI/ASME B18.2.4.1M  ASTM A#563M
ASTM F#467M
ASTM F#836M
ASTM A#194M 
hex, style 2  M3M36  ANSI/ASME B18.2.4.2M  
slotted hex  M5M36  ANSI/ASME B18.2.4.3M  
hex flange  M5M20  ANSI/ASME B18.2.4.4M  
hex jam  M5M36  ANSI/ASME B18.2.4.5M  
heavy hex  M12M100  ANSI/ASME B18.2.4.6M  
Metric PrevailingTorque Nuts  hex, steel  M3M36  ANSI/ASME B18.16.3M  ANSI/ASME B18.16.1M
ANSI/ASME B18.16.2M 
hex flange, steel  M6M20 
a. When only the property class number is shown, the class is standard in both ISO and ASTM documents. Properties specified in each are identical except for minor exceptions. Where differences exist, the F 568 values are given.
b. To compute the proof load, yield strength, or tensile strength in kilonewtons for a bolt, screw, or stud, divide the stress value, MPa as given in Table 10, for the property class by 1000 and multiply this answer by the tensile stress area of the product's screw thread as given in Table 9.
c. In general, identification markings are located on the top of the head and preferably are raised.
d. Class 5.8 products are available in lengths 150 mm and less.
e. Caution is advised when considering the use of Class 12.9 products. The capabilities of the fastener manufacturer, as well as the anticipated service environment, should be carefully considered. Some environments may cause stress corrosion cracking of nonplated as well as electroplated products.
TABLE 10
 
Property
Class Designation
 Nominal
Size of
Product
 Material and Treatment  Mechanical Requirements  Property
Class Ident. Marking
 
Proof
Load
Stress, MPa
 Yield
Strength, MPa, Min
 Tensile
Strength,
MPa,
Min
 Prod. Hardness, Rockwell  
Surface Max  Core  
Min  Max  
4.6  M5M100  low or medium carbon steel  225  240  400    B67  B95  4.6 
4.8  M1.6M16  low or medium carbon steel, fully or partially annealed  310  340  420    B71  B95  4.8 
5.8  M5M24  low or medium carbon steel, cold worked  380  420  520    B82  B95  5.8 
8.8  M16M72  medium carbon
steel; the
product is
quenched and tempered  600  660  830  30N56  C23  C34  8.8 
A325M Type 1  M16M36  A325M 8S  
8.8  M16M36  low carbon
boron steel;
the product
is quenched
and tempered  600  660  830  30N56  C23  C34  8.8 
A325M Type 2  A325M 8S  
A325M Type 3  M16M36  atmospheric corrosion resistant steel; the product is quenched and tempered  600  660  830  30N56  C23  C34  A325M 8S3 
9.8  M1.6M16  medium carbon steel; the product is quenched and tempered  650  720  900  30N58  C27  C36  9.8 
9.8  M1.6M16  low carbon
boron steel;
the product
is quenched
and tempered  650  720  900  30N58  C27  C36  9.8 
10.9  M5M20  medium carbon
boron steel;
the product is quenched and tempered  830  940  1040  30N59  C33  C39  10.9 
10.9  M5M100  medium carbon
alloy steel;
the product
is quenched
and tempered  830
 940  1040  30N59  C33  C39  10.9 
A490M Type 1  M12M36  A490M 10S  
10.9  M5M36  low carbon boron steel; the product is quenched and tempered  830  940  1040  30N59  C33  C39  10.9 
A490M Type 2  M12M36  A490M 10S  
A490M Type 3  M12M36  atmospheric
corrosion
resistant
steel; the
product is
quenched and tempered  830  940  1040  30N59  C33  C39  A490M 10S3 
12.9  M1.6M1000  alloy steel;
the product is quenched and tempered  970  1100  1220  30N63  C38  C44  12.9 
1. Units. The metric units used in electrical engineering and their symbols are shown below:
meter (m)
second (s)
candela (cd)
radian (rad)
steradian(sr)
ampere (A)
coulomb (C)
volt (V)
farad (F)
henry (H)
ohm ()
siemens (S)
watt (W)
hertz (Hz)
weber (Wb)
tesla (T)
lumen (lm)
lux (lx)
TABLE 11
QUANTITY  UNIT  SYMBOL 
length  meter, millimeter  m, mm 
frequency  hertz  Hz 
power  watt, kilowatt  W, kW 
energy  megajoule, kilowatt hour  MJ, kWh 
electric current  ampere  A 
electric potential  volt, kilovolt  V, kV 
resistance  ohm 
2. Rules for Electrical Engineering.
a. The only unit change for electrical engineering is the renaming of conductance from "mho" to siemens (S).
b. The lux (lx) is the unit for illuminance and replaces lumen per square foot and footcandle.
c. Luminance is expressed in candela per square meter (cd/m2) and replaces candela per square foot, footlambert, and lambert.
3. Conversion Factors. Table 12 identifies the conversion factors unique to electrical engineering.
TABLE 12
QUANTITY  FROM INCHPOUND UNITS  TO METRIC UNITS  MULTIPLY BY 
Power, radiant flux  W  W  1 (same unit) 
Radiant intensity  W/sr  W/sr  1 (same unit) 
Radiance  W/(srm2)  W/(srm2)  1 (same unit) 
Irradiance  W/m2  W/m2  1 (same unit) 
Frequency  Hz  Hz  1 (same value) 
Electric current  A  A  1 (same unit) 
Electric charge  Ahr  C  3600 
Electric potential  V  V  1 (same unit) 
Capacitance  F  F  1 (same unit) 
Inductance  H  H  1 (same unit) 
Resistance  1 (same unit)  
Conductance  mho  S  100 
Magnetic flux  maxwell  Wb  108 
Mag. flux density  gamma  T  109 
Luminous intensity  cd  cd  1 (same unit) 
Luminance  lambert cd/ft2 footlambert  kcd/m2 cd/m2 cd/m2  3.183 01 10.763 9 3.426 26 
Luminous flux  lm  lm  1 (same unit) 
Illuminance  footcandle  lx  10.763 9 
NOTE: Underline denotes exact number.
4. Conduit. Conduit will not change size in metric. It will be classified by a nominal mm size. The following paragraph and chart may be placed on the electrical drawing sheet.
"ALL CONDUIT SIZES ARE INDUSTRYSTANDARD ENGLISHSIZE CONDUIT DESIGNATED BY THEIR ROUNDED NOMINAL MILLIMETER (mm) DIAMETER EQUIVALENT. SEE CHART BELOW."
Nominal Size  
Inch  mm 
1/2  15 
3/4  20 
1  25 
11/4  32 
11/2  40 
2  50 
21/2  65 
3  80 
31/2  90 
4  100 
5  125 
6  150 
5. Cabling. Metric sizes are available.
a. Projects with medium and larger wire requirements may wish to start using international sizes, where permitted by governing codes and criteria.
b. ASTM B 682 gives metric sizes. Common sizes (in mm2) are, 0.5, 0.75, 1, 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120, 150, 185, 240, and 300.
c. Many projects have begun to refer to existing sizes by millimeter squared dimensions to become familiar with the millimeter squared scale. On the chart below are millimeter squared equivalents with detailed rounding. In some cases, rounding to the nearest 0.1, 1, or more square millimeters may be feasible. Use professional judgment.
AWG  mm2  kcm  mm2  
22  0.506  250  126.68  
20  0.517  300  152.01  
18  0.82  350  177.35  
16  1.31  400  202.68  
14  2.08  450  228.0  
12  3.31  500  253.4  
10  5.26  550  278.7  
9  6.6  600  304.0  
8  8.37  650  329.4  
7  10.6  700  354.7  
6  13.30  750  380.0  
5  16.8  800  405.4  
4  21.15  900  456.0  
3  26.66  1000  506.7  
2  33.63  1100  557.4  
1  42.41  1200  608.1  
1/0  53.48  1250  633.4  
2/0  67.44  1300  658.7  
3/0  85.03  1400  709.4  
4/0  107.2  1500  760.1  
1600  810.7  
1700  861.4  
1800  912.1  
1900  962.7  
2000  1013.4 
6. Fiber Optics. Most cables are made to metric dimensions, so these will be specified in hard metric (e.g., 125 m fiber cable). Illumination levels are in lux (lx).
7. Lighting Fixtures. Use hard metric fixture sizes for layin type. Common sizes are 600 x 600 mm and 600 x 1 200 mm. Use the 600 x 600 mm size with sockets on one end wherever possible as it is easier to manufacture in hard metric. Use either a compact tube or a T8 Utube for higher efficiency.
1. Units. The metric units used in mechanical engineering are listed below.
meter (m)
kilogram (kg)
second (s)
joule (J)
watt (W)
kelvin (K) or degree
Celsius (C)
pascal (Pa)
radian (rad)
newton (N)
TABLE 13
Quantity  Unit  Symbol 
length  meter, millimeter  m, mm 
volume  cubic meter  m3 
capacity  liter (1000 cm3)  L 
velocity  meter/second  m/s 
volume flow  cubic meter/second liter/second  m3/s L/s 
temperature  degree Celsius  C 
force  newton, kilonewton  N, kN 
pressure  kilopascal  kPa 
energy, work  kilojoule, megajoule  kJ, MJ 
rate of heat flow  watt, kilowatt  W, kW 
2. Rules For Mechanical Engineering.
a. The joule (J) is the unit for energy, work, and quantity of heat. It is equal to a newton meter (Nm) and a watt second (Ws), and it replaces inchpound units, such as ftlbf.
b. The watt (W) is both the inchpound and metric unit for power and heat flow. It replaces horsepower, foot poundforce per hour, Btu per hour, calorie per minute, and ton of refrigeration.
c. Moisture movement is expressed by the terms "vapor permeance" and "vapor permeability."
d. The inchpound unit "perm" continues to represent the degree of retardation of moisture movement. The lower the value, the greater the retardation.
e. The newton (N) is the derived unit for force (mass times acceleration, or (kgm/s2). It replaces the unit "kilogramforce" (kgf), which should not be used.
a. Temperature. Use Celsius for temperature measurements in new or modernization building projects. Renovation projects where the entire HVAC system is not to be renovated may retain Fahrenheit.
b. Air Distribution. Use a hard metric ceiling grid accompanied by hard metric layin diffusers and registers or smaller ones that are cut in.
c. Ductwork. Rectangular metal ductwork is a custommade product. Hard metric sizes are easier to measure (e.g., 300 x 600 mm). Prefabricated flexible round duct is specified in soft converted sizes.
4. Conversion. Table 14 below provides the conversion factors needed to adjust current plans to metric standards.
TABLE 14
Quantity  From InchPound Units  To Metric Units  Multiply By 
Mass/area (density)  lb/ft2  kg/m2  4.882 428 
Temperature  F  oC  5/9 (F32) 
Energy, work, quantity of heat  kWh Btu ftlbf  MJ J J  3.6 1 055.056 1.355 82 
Power  ton (refrig.) Btu/s hp (electric) Btu/h  kW kW W W  3.517 1.055 056 745.700 0.293 071 
Heat flux  Btu/(f2h)  W/m2  3.152 481 
Rate of heat flow  Btu/s Btu/h  kW W  1.055 056 0.293 071 1 
Thermal conductivity (k value)  Btu/(fthF)  W/(mK)  1.730 73 
Thermal conductance (U value)  Btu/(ft2hF)  W/(m2K)  5.678 263 
Thermal resistance (R value)  (ft2hF)/Btu  (m2K)/W  0.176 110 
Heat capacity, entropy  Btu/F  kJ/K  1.899 1 
Specific heat capacity, specific entropy  Btu/(lbF)  kJ/(kgK)  4.186 8 
Specific energy, latent heat  Btu/lb  kJ/kg  2.326 
Vapor permeance  perm (23 C)  ng/(Pasm2)  57.452 5 
Vapor permeability  perm/in  ng/(Pasm)  1.459 29 
Volume rate of flow  ft3/s cfm cfm  m3/s m3/s L/s  0.025 316 8 0.000 471 947 4 0.471 947 4 
Velocity, speed  ft/s  m/s  0.304 8 
Acceleration  ft/s2  m/s2  0.304 8 
Momentum  lbft/sec  kgm/s  0.138 255 0 
Angular momentum  lbft2/s  kgm2/s  0.042 140 11 
Plane angle  degree  rad mrad  0.017 453 3 17.453 3 
NOTE: Underline denotes exact number.
5. Heating, Ventilating, & Air Conditioning (HVAC). Air flow out of registers and diffusers should be rounded to even increments of 5 or 10 L/s wherever possible.
a. Ductwork (Round, Rigid). Most designers are showing hard metric diameters (e.g., 250, 300 mm).
b. Ductwork (Round, Flexible). Many designers are showing flexible round duct in hard metric sizes but are accepting soft metric during construction (e.g., 200 or 250 mm).
c. Ductwork (Rectangular). Use 50 and 100 mm sizes (e.g., 500 x 1000, 250 x 350) unless not possible.
a. Steel pipe, ASTM A 53, will not physically change. Pipe is classified by nominal mm sizes.
b. ASTM B 88 M hard metric copper tube sizes are available.
c. Schedule designations remain the same (e.g., Schedule 40, and type K, L, and M).
d. 18 mm may be used for 5/8 inch. All other designations remain the same.
e. The paragraph and chart below may be placed on the mechanical drawing sheet.
"ALL SIZES ARE INDUSTRYSTANDARD ASTM A 53 PIPE AND ASTM B 88 TUBE DESIGNATED BY THEIR NOMINAL MILLIMETER (mm) DIAMETER EQUIVALENT. SEE CHART BELOW."
Nominal Size  Nominal Size  Nominal Size  
Inch  mm  Inch  mm  Inch  mm  
1/2  15  2  50  5  125  
3/4  20  21/2  65  6  150  
1  25  3  80  8  200  
11/4  32  31/2  90  10  250  
11/2  40  4  100  12  300 
1. Flow rates, pressures, thermal powers, and other metric criteria on schedules should be rounded wherever possible. The one percent analysis provides a useful technique.
a. Example 1: A fan flow rate converts to 8,022 L/s. 1% is +/ 80.22 L/s. This fan could possibly be shown as minimum 8000 L/s (8 m3/s) and is easier to utilize.
b. Example 2: A pump flow converts to 75.7 L/s. One percent of this is 0.757 L/s. Therefore, 75 L/s could possibly be used.
2. It is important to note that, in some cases, codes or design criteria may not allow this liberty. In other cases, however, 2 or 3% analyses may be feasible, using your professional judgement.
a. Mechanical schedule temperatures, design temperatures, leaving and entering temperatures, and others shall be stated in even Celsius (e.g., 5, 12, 25, and 40 degrees C) unless this is not feasible.
b. Construction projects shall use Celsius only. Renovation projects where new control systems are being installed should also use Celsius.
c. HVAC calculations shall be in metric.
d. Thermal ratings for boilers and chillers should be specified in even nominal MW or kW increments (e.g., 2100 kW, 2 MW).
basic module: The fundamental unit of size in the systems of coordination in metric building construction: 100 mm (similar to inches in the inchpound system).
base units: In the metric system, the meter (length), kilogram (mass), second (time), kelvin (thermodynamic temperature), ampere (electric current), and candela (luminous intensity). The mole is also a base unit, but it a physics term and has no application in BLM work.
digit: One of the ten Arabic numerals (09).
degree Celsius: Related directly to thermodynamic temperature (kelvins). Unit of temperature. Zero degrees Celsius is equivalent to 32 degrees Fahrenheit (the freezing point of water) and 100 degrees Celsius is equivalent to 212 degrees Fahrenheit (the boiling point of water). A Celsius degree is 1.8 times larger than a Fahrenheit degree.
derived units: Units that are formed from base units, supplementary units, and other derived units, e.g., meters per second (m/s).
dimensional coordination: Special dimensional preferences for buildings and building products. In metric dimensional coordination, a common set of preferred dimensions is used to establish the geometry of a building as well as the sizes of constituent components or assemblies. Also called modular coordination.
dual dimensions: The expression of dimensions in both customary and metric units of measure.
hard conversion: Changing the actual size of a product so that its measurements are in rounded metric sizes.
inchpound measurement system: The foot, pound, gallon, degree Fahrenheit system used in the U.S.
inframodular size: A selected dimension smaller than the basic module (100 mm).
intermodular size: A selected dimension larger than the basic module (100 mm) but not a whole multiple of the module.
kilogram: Base unit of mass (weight). Symbol: kg. The kilogram is equal to 1000 grams and is approximately 2.2 pounds.
liter: Unit of volume or capacity used mainly to measure quanti ties of liquid or gaseous materials. It is equal to a cubic decimeter. Symbol: L. The liter is 6 percent larger than a quart. A smaller unit is the milliliter (mL), which is 1/1000 of a liter.
meter: The base unit of length. Symbol: m. The meter is equiv alent to 39.37 inches. Smaller units are the centimeter (cm), which is 1/100 of a meter (a little less than 1/2 inch), and the millimeter (mm) which is 1/1000 of a meter (a little more than 1/32 inch.) The kilometer (km) is a larger unit and is equal to 0.62 mile.
metrication: The process of converting to the metric system.
nominal value: A value assigned for the purpose of convenient designation; existing in name only.
preferred multimodular dimension: A selected multiple of the basic module of 100 mm.
rounded metric sizes: Sizes expressible in simple numbers based on nondecimal multiples of 1000, 100, 50, 20, 10, 5, 2, and 1 in order. Examples are 500 g, 1 kg, 2 kg, 500 ml, 1 L, 5 L, etc.
SI: Abbreviation for the modern metric system, the International System of Units (from the French, Systeme International
d'Unites). It evolved from the original French metric system and is currently being used virtually worldwide.
significant digit: Any digit that is necessary to define a value
or quantity.
soft conversion: The translation of customary unit measurements to their equivalent values in metric units.
supplementary units: The second class of metric units in the metric system. Units added to the system to enhance its capabilities. There are two units: radian (angles in one plane) and steradian (threedimensional angles).
TO CONVERT  MULTIPLY BY  TO OBTAIN 
acres  4.047 x 101 4.047 x 103 1.562 x 103 4.840 x 103  hectares sq. meters sq. miles sq. yards 
atmospheres  7.348 x 103 1.058 1.033 x 104 1.033 7.6 x 102  tons/sq. inch tons/sq. foot kgs./sq. meter kgs./sq. cm mm of mercury (0 C) 
acrefeet  4.356 x 104 1.234 x 103 3.259 x 105  cubic feet cubic meters gallons 
bars  9.869 x 101 1.0 x 106 1.020 x 104  atmospheres dynes/sq. cm kgs./sq. meter 
btu  1.041 x 101 1.055 x 103 2.928 x 104  literatmosphere joules kilowatthours 
btu/min  2.356 x 102 1.757 x 102  horsepower kilowatts 
candle/sq. cm  3.146  lamberts 
candle/sq. in  4.870 x 101  lamberts 
cubic feet  2.832 x 102 2.832 x 101  cubic meters liters 
cubic ft/min  4.720 x 101  liters/sec 
cubic inches  1.639 x 105 1.639 x 102  cubic meters liters 
cubic meters  6.102 x 104 3.531 x 101 1.308 1.000 x 103  cubic inches cubic feet cubic yards liters 
cubic yards  7.646 x 101 7.646 x 102  cubic meters liters 
cubic yds/min  1.274 x 101  liters/sec 
dynes/sq. cm  9.869 x 107 2.953 x 105 1.020 x 106  atmospheres in. of mercury (0C) kilograms 
ergs  7.376 x 108 1.000 x 107 2.773 x 1011  footpounds joules kilowatthours 
fathoms  1.8288  meters 
feet  3.048 x 102 3.048 x 101 3.048 x 104  millimeters meters kilometers 
feet/min  1.829 x 102 3.048 x 101 1.136 x 102  kilometers/hour meters/min miles/hour 
feet/sec  3.048 x 101 1.097 1.829 x 101  centimeters/sec kilometers/hour meters/min 
foot candle  1.076 x 101  lumen/sq meter (lux) 
footpounds  1.286 x 103 1.356 3.766 x 107  btu joules kilowatthours 
footlbs/min  3.030 x 105 2.260 x 105  horsepower kilowatts 
footlbs/sec  1.818 x 103 1.356 x 103  horsepower kilowatts 
gallons  3.785 x 103 3.785  cubic meters liters 
gallons/min  2.228 x 103 6.308 x 102  cubic feet/sec liters/sec 
gausses  1.0 x 104  webers/sq meter 
grams  9.807 x 105 9.807 x 103 2.205 x 103  joules/cm joules/meter (newton) pounds 
hectares  2.471 1.076 x 105  acres square feet 
horsepower  4.244 x 101 7.457 x 101  btu/min kilowatts 
hp (boiler)  3.352 x 104 9.803  btu/hour kilowatts 
hphours  2.547 x 103 2.684 x 106 7.457 x 101  btu joules kilowatthours 
inches  2.540 x 101 2.540 x 102  millimeters meters 
inches of mercury  3.342 x 102 3.453 x 102  atmospheres kilograms/sq. meter 
joules  9.486 x 104 1.020 x 101  btu kilogrammeters 
kilograms  9.807 2.2046  joules/meter (newton) pounds 
kilograms/sq cm  9.678 x 101 2.048 x 103 1.422 x 101  atmospheres pounds/sq foot pounds/sq inch 
kilograms/sq meter  9.678 x 105 2.048 x 101 1.422 x 103  atmospheres pounds/sq foot pounds/sq inch 
kilogrammeters  9.296 x 103 7.233 9.807 2.723 x 106  btu footpounds joules kilowatthours 
kilometers  3.281 x 103 1.094 x 103 6.214 x 101  feet yards miles (statute) 
kilowatts  5.692 x 101 4.426 x 104 1.341  btu/min footlbs/min horsepower 
kilowatthours  3.413 x 103 2.655 x 106 3.6 x 106  btu footpounds joules 
lamberts  3.183 x 101 2.054  candles/sq cm candles/sq inch 
liters  1.000 x 103 3.531 x 102 6.102 x 101 1.308 x 103 2.642 x 101 2.113 1.057  cubic centimeters cubic feet cubic inches cubic yards gallons (U.S.) pints (U.S.) quarts (U.S.) 
liters/min  5.886 x 104 4.403 x 103  cubic ft/sec gallons/sec 
lumen  7.958 x 102  spherical candle pwr 
lumen/sq foot  1.076 x 101  lumen/sq meter 
lux  9.29 x 102  footcandles 
meters  5.468 x 101 3.281 3.937 x 101 5.400 x 104 6.214 x 104 1.094  fathoms feet inches miles (nautical) miles (statute) yards 
meters/min  1.667 5.468 x 102 6.0 x 102 3.728 x 102  centimeters/sec feet/sec kilometers/hour miles/hour 
meters/sec  1.968 x 102 3.6 2.237  feet/minute kilometers/hour miles/hour 
miles (nautical)  6.076 x 103 1.852 1.1516 2.0254 x 103  feet kilometers miles (statute) yards 
miles (statute)  1.6093 8.684 x 101  kilometers miles (nautical) 
miles/hour  8.8 x 101 1.467 1.6093 2.682 x 101  feet/minute feet/second kilometers/hour meters/minute 
millimeters  3.281 x 103 3.937 x 102  feet inches 
ounces (avdp)  2.835 x 101 6.25 x 102 9.115 x 101  grams pounds ounces (troy) 
ounces (fluid)  1.805 2.957 x 102  cubic inches liters 
ounces (troy)  3.1103 x 101 1.097 8.333 x 102  grams ounces (avdp) pounds (troy) 
pints (dry)  3.36 x 101 5.0 x 101 5.506 x 101  cubic inches quarts liters 
pints (liquid)  1.671 x 102 2.887 x 101 4.732 x 104 4.732 x 101  cubic feet cubic inches cubic meters liters 
pounds (avdp)  4.536 x 102 4.448 4.536 x 101 1.458 x 101 1.215  grams joules/meter (newton) kilograms ounces (troy) pounds (troy) 
pounds (troy)  3.7324 x 102 1.3166 x 101 1.2 x 101 8.2286 x 101 3.7324 x 104  grams ounces (avdp) ounces (troy) pounds (avdp) tons (metric) 
pounds of water  1.602 x 102 1.198 x 101  cubic feet gallons 
pounds/cubic foot  1.602 x 102 1.602 x 101 5.787 x 104  grams/cubic cm kilograms/cu meter pounds/cubic inch 
pounds/cubic inch  2.768 x 101 2.768 x 104 1.728 x 103  grams/cubic cm kilograms/cu meter pounds/cubic foot 
pounds/sq. foot  4.725 x 104 1.414 x 102 4.882 6.944 x 103  atmospheres inches of mercury kilograms/sq meter pounds/sq inch 
pounds/sq. inch  6.804 x 102 2.036 7.031 x 102 1.44 x 102  atmospheres inches of mercury kilograms/sq meter pounds/sq inch 
quarts (dry)  6.72 x 101  cubic inches 
quarts (liquid)  5.775 x 101 9.464 x 104 1.238 x 103 9.463 x 101  cubic inches cubic meters cubic yards liters 
rods (survey)  5.029 5.5 1.65 x 101  meters yards feet 
square feet  2.296 x 105 1.44 x 102 9.29 x 102 1.111 x 101  acres square inches square meters square yards 
square inches  6.944 x 103 6.452 x 102 7.716 x 104  square feet square millimeters square yards 
square kilometers  2.471 x 102 1.076 x 107 1.0 x 106 3.861 x 101 1.196 x 106  acres square feet square meters square miles square yards 
square meters  2.471 x 104 1.076 x 101 1.55 x 103 3.861 x 107 1.196  acres square feet square inches square miles square yards 
square miles  6.40 x 102 2.788 x 107 2.590 2.590 x 106 3.098 x 106  acres square feet square kilometers square meters square yards 
square millimeters  1.076 x 105 1.55 x 103  square feet square inches 
square yards  2.066 x 104 8.361 x 101 3.228 x 107  acres square meters square miles 
temperature C  1.8 (+ 32)  temperature F 
temperature F (32)  5.555 x 101  temperature C 
tons (short)  9.072 x 102 2.0 x 103 2.43 x 103 9.078 x 101  kilograms pounds (avdp) pounds (troy) tons (metric) 
tons/square foot  9.765 x 103 1.389 x 101  kilograms/sq meter pounds/sq inch 
tons/square inch  1.406 x 106  kilograms/sq meter 
watts  3.4129 5.688 x 102 1.341 x 103 1.0  btu/hour btu/minute horsepower joules/second 
watthours  3.413 2.656 x 103  btu footpounds 
webers/sq inch  1.55 x 103  webers/sq meter 
yards  9.144 x 101 4.934 x 104 5.682 x 104  meters miles (nautical) miles (statute) 
PROJECT PLANS
(Illustrative Examples)
Project Plans  (Illustrative Examples)
Cabinets 5
Childcare Area 5
Door 6
Garage 8
Guard Rail 9
Landscape 10
Lintel 11
Lobby Renovation 12
Reflected Ceiling 14
Renovation Plan 15
Restroom 16
Security Desk 19
Stair 20
Storefront Detail 23
Wall Section 23
Window 26
The metric units in this guide are those adopted by the U.S. government (see the Federal Register of December 20, 1990; Federal Standard 376A, Preferred Metric Units for Use by the Federal Government; and PB 89226922, Metric Handbook for Federal Officials). They are identical to the units in the following publications, which constitute the standard reference works on metric in the United States.
ANSI/IEEE 268, American National Standard Metric Practice, and
ASTM E 380, Standard Practice for Use of the International System of Units (SI).
ASTM E 621, Standard Practice for Use of Metric (SI) Units in Design and Construction,
National Institute of Building Sciences, Metric Guide for Federal Construction and the Metric Construction newsletters
General Services Administration, M2: Metric Design Guide, Third Edition (October 1993).