Page 209 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch04.qxd 9/29/05 5:09 PM Page 4.37

BUILDING CODES, LOADS, AND FIRE PROTECTION*

BUILDING CODES, LOADS, AND FIRE PROTECTION 4.37

FIGURE 4.8 Some methods for applying gypsum as fire protection for structural steel: (a) column enclosed
in plaster on metal lath; (b) column boxed in with wallboard and plaster; (c) open-web joist with plaster ceil-
ing; (d) beam enclosed in a plaster cage; (e) beam boxed in with wallboard.

recommendations for mixing and application be followed closely. Fire-resistant designs are published
annually by Underwriters Laboratories (UL).
Adhesion/cohesion is an important characteristic of spray-applied materials, as covered in ASTM
E736. To ensure that it is attained, the structural steel should be free of dirt, oil, and loose scale;
generally, the presence of light rust will not adversely affect adhesion. When the steel has been painted,
however, field experience and testing have demonstrated that adhesion problems can arise. (Paint and

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