The manner in which home inspection requirements tackle firewalls is quite inconsistent. Although home inspection issues and firewall building code issues are not really cross-purpose, they are not perfectly aligned either. A firewall is an architecture designed to satisfy a double wish. For more info browse this site.
The motive behind firewall-related home inspection standards of practice is not to check that the building code has been followed so much as to assess if the dual purpose holds true. The first part of this desire is to prevent exhaust fumes, particularly carbon monoxide, which originate in the garage, from entering a residence’s living areas. The second part is focused on the premise that house fires are more likely to erupt in the garage; should this occur, the intention is to isolate the fire in the garage or at least postpone its spread to the proper house long enough to provide enough time for its inhabitants, particularly children, to evacuate.
The abstract idea of a firewall, then, is something that fulfills both parts of the desire for security. Building codes regulate the materialization of the theoretical idea, and years of putting the codes into action decide if the supposed objectives are accomplished.
Home inspection regulations simply circumvent the building codes and deal directly with the problem at hand. They stipulate that fire isolation between the house and the (attached) garage must be checked by the home inspector. The agreed interpretation of “fire separation” is that only after a time interval of at least one to two hours can a fire started in one space spread out to the other. In addition, the time delay must be retained for all possible routes, both directly through windows and doors and indirectly through ceilings and uppers.
Clearly, it is difficult to calculate delay of fire penetration during the course of a home inspection. The home inspector must therefore go one degree further away from the abstract idea and use guides which translate the implementation of certain construction practices and materials into an expected delay in penetration. Worries over pedestrian doors between garage and house and questions over drywall thickness are what everything comes down to for inspectors.
Home inspectors test to have a strong core at the pedestrian door(s) and to be marked as fire. A fire-rated door typically has a mark on the side of the door where the hinges are installed which identifies it as such. Inspection requirements waive the need for fire rating determination when the mark is not in place. The solid core and fire rank, at any rate, yield a satisfactorily anticipated delay in penetration.
For both walls and ceilings, the correct drywall thickness has been empirically determined to be 1⁄2 inch. Home inspectors can’t really accurately check this, but the edges of the drywall are often visible in unfinished spaces and attic hatches. Building codes and inspection regulations match here, so that if the design of a house has gone through the correct channels, the inspector can be fairly sure that the thickness of the building inspectors has been checked.