Fire Suppression Systems
This month's panel discusses the issues that engineers and designers need to be aware of concerning fire suppression systems, extinguishants and codes. CSE: What questions should designers ask their clients at the start of a project for a new fire suppression system? KELLY: For new projects, the designer should ask the client or owner several basic questions that are vital to the design of the ...
This month's panel discusses the issues that engineers and designers need to be aware of concerning fire suppression systems, extinguishants and codes.
CSE: What questions should designers ask their clients at the start of a project for a new fire suppression system?
KELLY : For new projects, the designer should ask the client or owner several basic questions that are vital to the design of the system. What city or town will the building be located in? The location will determine the applicable codes. What is the proposed height and area of the building? What is the use of the facility and what will all of the rooms/spaces be used for? This information is used to help determine the hazard classification, which can dictate water supply criteria.
Will a water-based fire suppression system be sufficient or will a non-water based extinguishing system be needed? Is there any storage—how is the storage arranged and is it hazardous? Is any water-flow testing information available and how current is it? Have the water flow results been modified to account for the highest water demand of the day and of the year? If the fire protection water supply is fed from a public water main, are there any local water department specific requirements? Are there any anticipated major future projects in the vicinity that might modify the available water supply? A change in the water supply could require the addition of a fire pump to supply adequate pressure to the system.
JELENEWICZ : When designing a new fire suppression system, the engineer is responsible for developing design documents, which establish the objectives and design criteria of the system. Therefore, it is important for the engineer to ask questions that will help the engineer identify the occupancy type and hazard classification for the area being protected. I agree with Kevin. It is important when designing water-based fire suppression systems to ask for existing water supply data so that the available water supply can be confirmed.
CAPPUCCIO : There are several important questions that designers should gain insight from early in the design process. First, what is the objective of the project—are there particular hazard concerns or concerns related to the impact of suppression on the building or mission continuity? And a question that can be challenging, to fully understand as to its impact on a project, is integration of fire protection and other systems such as security, mechanical, smoke control and door closures.
CSE: What questions should designers ask their clients at the start of a project for a replacement fire suppression system?
CAPPUCCIO : Certainly the same questions as identified for new systems are important for replacement systems. Also of great importance with replacement systems is phasing. What is the installation sequence? Will floors or parts of a floor be vacated during the installation? Will the building need to remain fully functional during the replacement installation? This direction needs to be provided to the installing contractor through the design documents. The phasing of the project can be critical to the project's success.
JELENEWICZ : If a fire suppression system is going to be replaced, it is a good idea for the engineer to get all of the available test and maintenance data for the existing system. When designing a water-based fire suppression system, this data can assist in identifying any deficiencies in the existing water supply that may need to be corrected during the design of the new system.
KELLY : For existing structures or replacement systems, the designer should ask the client or owner the same questions as for new projects as well as some additional questions more specific to existing systems.
What is the extent of the replacement work? Has the occupancy classification or use of the building changed? How accessible is the interior of the floor/ceiling assemblies and walls? What is the extent of repairing and replacing the interior finish? How flexible is the building owner with regard to building accessibility and project scheduling? Will this affect the labor for the project, for example, night and weekend work as opposed to working during business hours?
In addition, will system pressure or water supply demands be increased, which could require the addition of a fire pump? Will there be any anticipated increase in water flow that could require a larger fire suppression supply main. Consult with the water department to help determine if system revisions will require the addition of a backflow preventor and if there will be any anticipated fees.
CSE: What issues involving the integration of extinguishing systems and alarm panels challenge designers?
CAPPUCCIO : An experienced designer should know the types of items that impact the integration of extinguishing systems and fire alarm systems. Using one entity to design both systems should enhance the likelihood that items requiring integration will be properly addressed. This is a more challenging task when one entity designs the suppression system and another designs the fire alarm system. Typical features that require integration are flow and tamper switches, but other features that need to be considered between fire alarm and extinguishing systems include: special suppression system release panels, such as pre-action or deluge systems and kitchen suppression systems.
JELENEWICZ : It is essential that the design of the extinguishing system be coordinated with the design of the fire alarm system. For example, all of the flow indicators, pressure switches and tamper switches for a suppression system need to report to the fire alarm system. It also is important to specify which of these devices indicate an alarm condition and which devices indicate a supervisory condition.
KELLY : When integrating fire alarms and extinguishing systems some basic system design functions should be determined. Does the system need to be addressable or can it be a zoned system? Zones for fire alarms and zones for suppression systems might include different areas and requirements. Will the capacity of the fire alarm be capable of the number of addressable points? Ensure that any specific requirements for elevator shafts and elevator machine rooms include the correct emergency functions during a fire alarm.
Also review the local codes to determine if suppression is required in elevator shafts or elevator machine rooms as this will be specific to a jurisdiction.
CSE: What fire suppression product developments are the most useful and cost-effective in the past several years?
JELENEWICZ: There have been some great technological advances in development of extended coverage sprinklers. These extended coverage sprinklers are especially advantageous as a way of decreasing the number of sprinklers required to protect a specific area. As a result, engineers will find that installation costs should be lower.
There also has been technological advances in early suppression fast response (ESFR) sprinklers. ESFR sprinklers protect storage facilities that have high-piled and rack storage without having to install costly in-rack sprinklers.
CSE: What fire code issues commonly trip up design engineers?
KELLY : Certain fire suppression liquids or agents could require additional levels of protection. For example, a backflow preventor could be required for an antifreeze system or suppressant runoff containment could be required for foam or chemical suppression systems after system activation.
CAPPUCCIO : First, having a strong understanding of the nationally recognized codes and standards is important. I do not know of a jurisdiction that doesn't use some version of the nationally recognized codes and standards with regard to fire suppression and fire alarm and notification systems design.
Once that basic requirement is mastered, designers need to be aware of local amendments. Having a local presence allows designers to be aware of the local jurisdiction requirements, but also aids in developing a relationship with the local code officials that allows for a better exchange of information and a more proactive approach identifying and resolving conflicts.
CSE: What long-term operational issues should fire protection engineers treat very seriously during the design phase?
JELENEWICZ : Although this may seem simple, all valves and test connections should be located where they are easily accessible to facility managers, so the system can be tested and maintained properly. Therefore, it is helpful to identify the location of all valves and test connections during design.
KELLY : Long-term operational issues need to address inspection, testing and maintenance concerns. For example; standpipes with pressure reducing valves require the addition of a 3-in. drain riser to facilitate the testing of the pressure-reducing hose connection valves.
Also, engineers may find that the addition of a test header is required, which is capable of handling the full system demand flow for testing the backflow preventor. The control of large volumes of water runoff from testing the system also should be addressed. Additionally, a long-term anticorrosion plan is probably more cost-effective than corrosion treatment.
CSE: What are the first-cost drivers on an extinguishing system? What issues drive life-cycle cost?
KELLY : The first-cost driver for extinguishing systems is based on the type of system required by the code. Water-based systems probably cost less than a non-water based system. Other cost drivers include the availability of an acceptable water supply, which will determine whether a fire pump is required or not. System life-cycle costs are partially governed by the type of system used.
For example, a wet-pipe system will probably require less maintenance costs during the systems life as compared to a dry-pipe system, which will probably require more maintenance. A simple cost/benefit analysis will be useful in determining the true system cost when comparing installation cost vs. maintenance costs.
JELENEWICZ : Without a doubt, determining the water supply is a major first-cost issue when designing water-based fire suppression systems. As such, it is imperative that the engineer verify the existing water supply data and carefully plan the most cost-effective water supply for the given application.
When designing water-based suppression systems for unheated spaces, life-cycle cost is always an issue. Therefore, the engineer should consider all of the options for protecting an unheated space with a water-based system. For example, if the area is small, the life-cycle cost of maintaining an area that has drypendant sprinklers is much more cost effective than a system that has a dry-pipe valve with all of the trim.
CAPPUCCIO : For sprinkler systems, first-cost drivers relate to several factors. First, is a fire pump required? The height of the building, the quality of the water supply and the hazard of the building contents combine to determine whether a fire pump is needed. The first cost of a fire pump needs to be compared with the costs of potentially larger sprinkler piping. In addition to the fire pump, other equipment is needed including emergency power for the fire pump in some circumstances.
Another issue that affects first costs of extinguishing systems is the type of system. Is a pre-action system desired to address a concern for unwanted sprinkler discharge?
As for life-cycle costs, the more complex the suppression system, the greater the need for maintenance, the greater the opportunity for system component failures results in greater life-cycle costs. So, this Roundtable's first question: “What should designers ask their clients…?” is a really important question, and a part of that discussion should include this topic of first and life cycle costs as compared with the advantages and features of various suppression systems.
Joseph Cappuccio, P.E.
Regional V.P.of Rolf Jensen & Assocs.' Eastern Region, Chicago
Chris Jelenewicz, P.E.
Engineering Program Manager, Society of Fire Protection Engineers, Bethesda, Md.
Kevin J. Kelly, P.E.
Schirmer Engineering, New York