This page was written by Steven J. DeRose in March of 2003, and was last updated 2005-04-06.
This page provide copies of and pointers to some useful engineering reference data. I'm not an engineer myself, I just find I need this kind of information from time to time, and hate digging it up over and over.
There are richer sets of engineering reference information at these sites:
Densities of various materials
Diameters, torque, and strength of standard bolts and threaded rods.
Fractional inch, decimal inch, and mm equivalents (from 1/64 to 63/64 inch)
Joist span-length tables
Footing depth and size for various loadings. This depends main on the load-bearing capability of the soil the footing sits on (whether the house is built on rock or on sand, for example), and the total load that has to be held up. Footings are normally reinforced with steel rebars. Some good information is available from the Concrete Network.
Blast pressure resistance of various materials
R-values of various materials: http://coloradoenergy.org/procorner/stuff/r-values.htm, or a local version here.
Gas permeability of various materials: See here, and a local copy here.
Air-flow in various duct sizes -- See my Emergency Preparedness Guide
Water-flow in various pipe sizes -- (not here yet, sorry).
Gamma-ray shielding by thickness/weight of materials -- a fair estimate is that 150 pounds of mass per square foot (such as about a foot of concrete) will stop 90% of incident gamma rays: a "protection factor" of 10. A protection factor of 40 is reasonable for a home shelter (that means 19 inches of concrete, not 4 feet).
AWG wire gauge diameters and current capacities.
Medical needle gauges -- these are fairly close to AWG wire gauges, but not quite the same, at least according to the sources I've been able to find. I don't know who defined this standard.
Flame temperatures for various heat sources, from light-bulbs to plasma torches, are here.
Fire-resistance of various materials is rated in several ways, described by Armstrong Corporation here. Two common ratings are "flame spread" and "smoke developed" (for example, these values are generally printed on the back of fire-rated drywall sheets). The "fire resistance rating" in hours is determined by an entirely different test defined by standards NFPA No. 251, ASTM E 119, and UL No. 263.
Note: Vseal sells a highly Fire-resistant paint that can be used to upgrade firewalls, make a wood wall fire-resistant, etc. However, it doesn't seem to be listed directly on their web-site. You can call them at 877-73V-SEAL for more information. Sounds like an excellent idea for painting garages, laundry rooms, and furnace rooms (though I have no idea what status this may have in various building codes). Urethane foam adds considerable fire resistance when covered by another surface material such as drywall.
Flame spread ratings are used in building codes to determine what materials may be used in certain situations. They are defined by ASTM E-84, Standard Test Method for Surface Burning Characteristics of Building Materials:
| Class | Flame Spread Range | Example Locations |
|---|---|---|
| I or A | 0-25 | Enclosed vertical exits |
| II or B | 26-75 | Exit access corridors |
| III or C | 76-200 | Other rooms and areas |
| IV or D | 200+ | (?) |
A description of the test method and the classes is available from the American Wood Council here. They also supply a table of flame spread values for specific wood materials here. For example, Hemlock and Fir species (commonly used for dimensional lumber) have a rating of 60, various plywoods are about double that.
The Canadian Wood Council provides flame-spread and smoke-developed rating for common constructions materials here. For example, gypsum wallboard has values of 25 (FS) and 50 (SD), while typical lumber is 150 and 300, while hardwood flooring is even worse. These measures are useless for metal, which generally doesn't burn but weakens with temperature instead.
Fire-resistance times for various materials are available from the National Agricultural Safety Database, or in a simpler local form here. Concrete seems clearly the material of choice for fire resistance.
T.C. Forensics provides good information on ignition and burning temperatures here.
The Engineering Toolbox has a section for ignition temperatures of various fuels, for boiling points of various fluids, as well as much other useful information.
One article is here. It includes price per square foot for the variety of wall types tested. The most cost-effective was standard 2x4 framing, faced by 1/2" plywood and then concrete-filled, faced on one side with 5/8" wallboard. It stopped all of 9mm, .45 auto, .357, .44, 12 ga. Slug, .223, and .270 Win, at a cost of about $45 per running foot of wall (versus about $15 per running foot of a typical, non-resistant wall). Standard 2x4 framing with 1/4" steel plate on one side and 5/8" wallboard on the other, stopped all but the last two and cost about $95 per running foot of wall.
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