When responding to this type of development thoughts of "conflagrations" and other severe fires of the past come to mind. If this type of "retro" development becomes mainstream, modern residential building codes must address the importance of residential sprinkler systems and the advantages to having these types of systems used as a direct component of construction. Other forms of fire resistive elements must be installed but the residential sprinklers should be the main focus of construction.
NFPA 13-D and 13-R Residential Sprinkler Systems should be viewed as the "first responder" in residential construction. The application of water on fires at or slightly above incipient phase could save countless lives and property. Even with water damage losses factored in, sprinklers could save insurance companies unknown amounts of money.
Fire department operations and tactics must be revisited to include residential fire sprinklers. Firefighters must understand that when attacking a fire in a sprinklered residential structure, tactics similar to those employed in sprinklered commercial buildings are applicable. Fire containment and control must be achieved before sprinklers are shut down. A special precaution when shutting down a domestic water supply to a sprinklered structure involves the use of a single control valve arranged to shut off both the domestic system and the sprinkler system. This valve arrangement can be utilized for systems with common sprinkler/domestic water supplies. Fire units turning off utilities to a structure could mistakenly contribute to fire growth and endanger interior crews if this type of valve configuration is used to supply a sprinkler system. This problem reinforces the need for proper pre-planning to be conducted in residential sprinklered structures.
Differences in the design, piping, and valves of residential sprinkler systems are important areas of concern and must be understood. Traditional NFPA 13 Fire Sprinkler Systems are designed with the concept of "property conservation." The design method of residential fire sprinkler systems utilizes the concept of "life safety," The differences between these design methods are emphasized in the installation of the types of heads and the required locations of heads. In NFPA 13 installations, all areas of the building are required to be sprinklered with no exceptions being granted by the code. Examples of this include: interior construction creating an obstruction of more than four feet in width, rack storage units, machine and ovens, spray booths, and in some instances exterior overhangs. Sprinkler heads used in these types of systems are UL Listed Standard Orifice Heads, Extra Large Orifice and Early Suppression Fast Response (ESFR) Heads. Types of systems installed are wet, dry, pre-action, ESFR and Deluge Systems.
Residential fire sprinkler systems utilize the concept of "life safety." The design of these systems requires the installation of heads in inhabitable spaces of a structure. Exceptions are given to this rule in bathrooms with an area that does not exceed 55 square feet. Sprinklers are not required in clothes closets, linen closets, and pantries that do not exceed 24 square feet. With this exception, walls and ceilings, including walls and ceilings behind fixtures, must be made of noncombustible or limited-combustible materials that provide a 15-minute thermal barrier.
Sprinkler heads are not required in attics, penthouse equipment rooms, elevator machine rooms, concealed spaces dedicated exclusively to and containing only dwelling unit ventilation equipment, crawl spaces, floor/ceiling spaces, elevator shafts, and other concealed spaces that are not used or intended for living purposes or storage and do not contain fuel-fired equipment. Heads are also not required in any porches, balconies, corridors, and stairs that are open and attached to the building.
These systems may use metallic or non-metallic pipe and components designed for working pressures of not less than 175 psi with an 1 1/2-inch fire department connection (FDC). In some rare cases, due to inaccessibility by the fire department or single-story construction, a FDC may not be installed on the system). Fire Departments must either require 2 1/2-inch connections to be installed during plan review on systems or modify company tactics to include 1 1/2-inch hose to be used as supply line in sprinkler support operations. When pumping a residential system, pump pressures must be adjusted downward to offset lower system operating pressures. Excessive pump pressures may damage the system and, at a worst-case scenario, cause piping to burst rendering the system inoperative. Pre-planning once again will identify the correct pump pressures needed to properly support these systems. Valve sizes incorporated are smaller and require minimal effort to shut off utilities. Some common components utilized in both NFPA 13 and 13-R/D systems include among others, system and supply pressure gauges, inspector test valves and main drain valves.