Fire Protection Systems: One Size Does Not Fit All
Recent legislation and a higher concern for life safety have created a major increase in fire detection and alarm system modifications. When it comes to designing and specifying these modifications, the engineer must consider many items that may have a significant impact on the ultimate construction. Also, several jurisdictions now are requiring the fire detection and alarm system to be fully designed prior to issuance of a building permit. Of course, with fully designed systems, unknowns in design development can lead to change orders in construction.
The first consideration must be the applicable code. Many factors determine which code applies to a particular installation. The Uniform Building Code (UBC), the Uniform Fire Code (UFC) and appropriate National Fire Protection Assn. (NFPA) codes should all be reviewed carefully to determine which codes apply. In addition, local codes and the Americans with Disabilities Act (ADA) are also to be enforced. Typically, codes will have changed since the original installation, which means that the existing system may not meet current versions of the codes; to replace the existing fire alarm system exactly as installed would be a huge mistake.
A typical scenario might involve facility occupancy changing, due to code changes, thus requiring a different system type (speaker vs. horns). There is no shortcut to a thorough investigation of all applicable codes prior to beginning a project. In some cases code changes have required facilities to make dramatic updates. For example, in California, the Green Oaks Family Academy Elementary School Fire Protection Act (SB 575) now requires an automatic fire detection and alarm system for all facilities serving grades K through 12.
Often, as with the Green Oaks Act, the full enforcement of the code depends on the budget or extent of the project. Usually, fire detection and alarm modifications are a byproduct of another driving project. The more significant the primary project, the more extensive the retrofit of the existing fire detection and alarm system.
But the modification must also fit within the budget constraints placed on the overall project. Initial budgeting of the fire detection and alarm system should be made to ensure the owner and all participants are fully aware of the impact. The cost of installing new systems, no matter how great, can always be daunting. Often, the labor to install a new system far outweighs the cost of the equipment. For example, replacing an existing manual system with a new automatic system may require extensive rewiring within difficult-to-reach spaces.
Look before you leap
A thorough review of the existing facility and system should be made. Often, as-built fire detection and alarm drawings or calculations do not exist. The location and type of all devices should be noted during this review of the facility. All spaces should be reviewed to determine which devices and what quantity of devices will be required. In addition, many back boxes for existing pull stations and notification appliances may need to be relocated, as these devices may not meet the current criteria established in ADA. Another consideration is that the existing system is a "line voltage" system, which either only marginally functions or for which parts can no longer be obtained.
There are many system types to choose from: analog, digital, one-loop, Class B, etc. These options should be discussed with the user and maintenance personnel. The engineer should also determine the fire-protection system user and facility maintenance personnel preferences and proficiencies. The system should be specified to match the expertise of the individuals who will be operating and maintaining the system. In addition, the location of the main panel as well as the location of any annunciation panel should be discussed with users and the project architect.
The system will require constant monitoring by a certified off-site facility, the kind of service offered by providers such as ADT. A phone line with dial tone will be required at the fire alarm panel. Many of the new PBX systems allow for a direct-dial tone. The extension of this line should be coordinated with information technology personnel or telephone technicians.
Future expansion and flexibility should be considered when it comes to sizing the system. To install a system that is fully utilized right away would be providing a disservice to the owner. Having said this, the system should also be sized to the facility. Expensive, highly responsive equipment may be of little use to the user in a smaller facility where such characteristics are not crucial.
In addition to the above, many other factors must also be considered. The location of devices is well-defined within NFPA codes. However, existing conditions may make these placements impractical. The use of multi-candela strobes can be very useful in retrofitting an existing facility. Care should be taken to ensure each notification appliance circuit has sufficient capacity to allow for the increase in candela levels without overloading the NAC or adversely affecting the voltage-drop calculations.
Whenever new devices are to be placed in an existing facility, wall or ceiling openings will need to be created. Location of access panels and devices should be carefully coordinated with the architect. We recommend the architect place each of the new devices on the elevation drawings. This will ensure no device will be located behind a new shelving unit. Access to many of the spaces requiring new devices may be limited. In addition, once access has been obtained, surprises like large beams may be found. This would reveal many more spaces above the ceiling requiring heat detection.
Finally, the new fire detection and alarm system may need to interface with other existing devices or other alarm panels. Designers should find out as much information as possible on these devices before the system is designed. Voltage compatibility, addresses and contact compatibility are only a few of the items that should be considered. Often, additional interface modules are required to activate, deactivate or otherwise monitor existing devices. Some typical devices include elevator recall, duct smoke detectors, fire smoke dampers, fire curtains and smoke removal systems.
The more the engineer knows about an existing system and facility, the more informed his or her decisions will be. These better decisions will ensure better system installation. This, of course, will lead to a better overall system that will better meet the needs of the user.