Bolt dimensions, material, coating, proofload and clampload torque values to be used are information typically found on an American National Standards Institute bolt torque chart. There is a variety of bolt types and uses, with each one having multiple variables on the safest and most effective usable torque values.
Torque and tension values can be affected by human error, bolt lubrication and surface texture. They must be tested in the actual environment in which the bolt is being used to get accurate values as to the safe percentage of load that can be used.
Typically, bolts are torqued to the point of failure in order to find their proofload. The proofload is set at 92 percent of the failure point and that is the torque value that is stamped on the bolts head. The clampload value on the torque charts is usually 75 percent of the proofload and is used to allow for a safety margin in actual construction applications. Bolts under 7/16-inch are usually measured in inch-pounds of torque, while those larger are represented in foot-pounds.
Users that have questions on ANSI bolt torque loads can access the full range of charts on their iPhone. The iTite app allows users to calculate values from 30 to 100 percent of use load.