Building Design and Construction Handbook - Merritt - Ventech!

3.28 SECTION THREE
and aqueous dispersions are usually applied by brush or spray. Most of these coatings
are vapor barriers but some textured coatings, conventional paints, and aqueous
dispersions are breathers. Except for the aqueous dispersions, all the coatings are
recommended for use with a primer.
Applied as a continuous coating, without pinholes, the pigmented organic coatings
are highly water-resistant. They are most effective when applied over a smooth
backing. When they are applied with paintbrush or spray by conventional methods
to rough-textured walls, it is difficult to level the surface and to obtain a continuous
water-resistant coating free from holes. A scrubbed-on cementitious grout used as
a base coat on such walls will prevent leakage through the masonry without the
use of a pigmented organic coating.
The pigmented organic coatings are highly decorative but may not be so waterresistant,
economical, or durable as the cementitious coatings.
Bituminous Coatings. Bituminous cutbacks, emulsions, and plastic cements are
usually vapor barriers and are sometimes applied as ‘‘dampproofers’’ on the inside
faces of masonry walls. Plaster is often applied directly over these coatings, the
bond of the plaster to the masonry being only of a mechanical nature. Tests show
that bituminous coatings applied to the inside faces of highly permeable masonry
walls, not plastered, will readily blister and permit leakage of water through the
coating. It is advisable not to depend on such coatings to prevent the leakage of
wind-driven rain unless they are incorporated in the masonry or held in place with
a rigid self-sustaining backing.
Even though the walls are resistant to wind-driven rain, but are treated on their
inner faces with a bituminous coating, water may be condensed on the warm side
of the coating and damage to the plaster may result, whether the walls are furred
or not. However, the bituminous coating may be of benefit as a vapor barrier in
furred walls, if no condensation occurs on the warm side.
See also Secs. 9 and 11.
(‘‘Admixtures for Concrete,’’ ACI 212.1R; ‘‘Guide for Use of Admixtures for
Concrete,’’ ACI 212.2R; ‘‘Guide to Joint Sealants for Concrete Structures,’’ ACI
504R; ‘‘Specification for Materials, Proportioning and Application of Shotcrete,’’
ACI 506.2; ‘‘A Guide to the Use of Waterproofing, Dampproofing, Protective and
Decorative Barrier Systems for Concrete,’’ ACI 515.1R; ‘‘Specification for Concrete
Masonry Construction,’’ ACI 531.1; ‘‘Polymers in Concrete,’’ ACI 548R; ‘‘Guide
for the Use of Polymers in Concrete,’’ ACI 548.1R, American Concrete Institute,
P.O. Box 19150, Redford Station, Detroit, MI 48219.)
3.5 PROTECTION AGAINST FIRE
There are two distinct aspects of fire protection: life safety and property protection.
Although providing for one aspect generally results in some protection for the other,
the two goals are not mutually inclusive. A program that provides for prompt notification
and evacuation of occupants meets the objectives for life safety, but provides
no protection for property. Conversely, it is possible that adequate property
protection might not be sufficient for protection of life.
Absolute safety from fire is not attainable. It is not possible to eliminate all
combustible materials or all potential ignition sources. Thus, in most cases, an
adequate fire protection plan must assume that unwanted fires will occur despite
the best efforts to prevent them. Means must be provided to minimize the losses
caused by the fires that do occur.