Snug-tightness is the tightness that is attained with a few impacts of an impact wrench or the full effort of an ironworker using an ordinary spud wrench to bring the connected plies into firm contact. The applications for which pretensioned instead of snug-tightened bolt assemblies are required can be found within Clause 22.2.2 of the S16-14:
a) slip-critical connections where slippage cannot be tolerated (e.g. connections subject to fatigue or frequent load reversal, or connections in structures that have rigorous deflection or stiffness limit states);
b) shear connections, when required by Clause 27.1;
c) all elements resisting crane loads;
d) connections subject to impact or cyclic loading;
e) connections where the bolts are subject to tensile loading (see Clause 13.12.1.3); and
f) connections using oversize or long slotted holes (unless specifically designed to accommodate movement).
Few joints in commercial or residential building construction are subject to frequent load reversal, nor are there many situations where a one-time slip into bearing cannot be tolerated. In addition, for typical building structures, full wind loads are too infrequent to warrant design for fatigue. Therefore, pretensioned and/or slip-critical connections are not normally required in buildings for wind load combinations. For seismic applications, refer to Clause 27 of S16-14.
In building construction, the norm for bolted connections in shear is snug-tightened bearing-type connections.
