We have seen them so often that we pass by without a second thought; those spiked round devices hanging just below the ceiling. Sprinkler Heads. They may sit there for many years, doing nothing but adding to the maintenance costs of the building. They provide no benefit until that one day, when their proper function will save lives and investment.
Sprinkler systems are complex, expensive, and don’t add any appeal to your building's architecture but when they are needed they become the most important component of a structure.
What are they all about?
The purpose of the fire sprinkler system is simple: to provide an appropriate amount of water to extinguish fires before they get the opportunity to grow and spread throughout the room. There are also various types of sprinkler systems that will provide the right kind of protection for the specific kind of setting in which they are installed. The types of fire sprinkler systems include wet pipe, dry pipe, deluge, and preaction fire sprinkler systems.
- A wet pipe sprinkler system is the most common type. The sprinkler heads connect to pipes that are filled with pressurized water. When a fire is detected, the sprinkler system activates automatically to extinguish the fire. It is a reliable fire sprinkler system that requires little maintenance.
- With dry pipe sprinkler systems, the sprinkler heads connect to pipes that are filled with pressurized air or nitrogen that holds back the water. If a fire occurs, the pressure in the piping drops, and a valve opens to allow water to extinguish the fire. Dry pipe sprinkler systems are ideal for environments where temperatures drop below 40⁰ F since the pipes do not hold water.
- A deluge fire protection system has unpressurized dry piping and open sprinkler heads. The system is directly connected to a water supply and when the system is activated, a deluge valve will release the water to all the open sprinkler heads simultaneously in high hazard areas such as aircraft hangars or chemical plants.
- Pre-action fire sprinkler systems employ the basic concept of a dry pipe system in that water is not normally contained within the pipes. The difference, however, is that water is held from piping by an electrically operated valve, known as a pre-action valve. For this reason, pre-action systems are frequently employed in water sensitive environments such as archival vaults, fine art storage rooms, rare book libraries and computer centers.
Sprinkler systems are specifically designed to address certain levels of hazards.
- Light Hazard - Examples of buildings in this category include bakeries, beauty salons, barber shops, doctors’ offices, canneries, office buildings, and municipal buildings.
- Ordinary Hazard - Ordinary hazard buildings might include malls, light manufacturing or research operations, parking garages, workshops, automobile showrooms, electronics plants, laundries, and restaurants
- Moderate Hazard -Some examples of moderate hazard buildings include dairy barns, cold storage warehouses, manufacturing and clothing plants, amusement occupancies such as an arcade, machine shops, and some commercial kitchens.
- High Hazard - Buildings in this category have a high content of combustibility and quantity, so if a fire started here it would likely rapidly develop and have an enhanced heat release rate. Examples include department stores, stables, barns, feed stores, freight terminals, pulp and paper mills, and warehouses storing paint, furniture, or paper.
- Severe Hazard - Any fires that began in these locations would spread quickly and burn incredibly hot, making them difficult to put out. Some of the buildings that commonly require the severe hazard fire sprinkler classification are aircraft service terminals, storage warehouses, sawmills, metal extrusion factories, plywood production, rubber manufacturing, and textile manufacturing.
There can be more than one hazard rated area within the same building. The systems are designed using the proper quantity of type of components and with the proper water supply to handle the correct hazard.
Here are some of the basic parts of a sprinkler system.
- Riser - A fire sprinkler riser serves as a hub for drainage, tests, and system control. This is the series of pipes you can't miss when you look at the sprinkler system.
- Control Valve - To assess loss of pressure over time during testing and to verify the water pressure in a system.
- Main Drain - Allows the system to be drained down for maintenance, interior inspections, repair, or modifications.
- Inspectors Test - Allows the waterflow switch to be tested as required by NFPA 25 by flowing water, and allows drainage of the system.
- Fire Department Connection - Allows the fire department to supply supplementary pressure and flow to the system during a fire event.
- Alarm - The alarm is tied to the system to alert occupants and emergency personnel that an event has occurred that activated the sprinkler system.
- Sprinkler Heads - For most occupants and visitors of a building, this is the most recognized part of the sprinkler system and the biggest clue that there is a fire sprinkler system present. The sprinkler heads are made in many types and sizes depending on the fire response needs of the space.
Testing and Sprinkler Credit
Many builders and building owners don’t even realize that they may not get full credit, or often any credit at all, for their expensive sprinkler system when it comes to insurance.
What are the most common reasons for loss of credit?
- No “As-Built” plans are available, a common issue for older buildings that have changed ownership over the years.
- No maintenance or deferred maintenance and testing. Inadequate maintenance could cause a sprinkler system to fail.
- Sprinkler system is not designed for current occupancy. As occupancy changes or tenants move in and out of a building, the sprinkler system could be inadequately designed for the occupant type.
- Storage is higher than the system’s designed capacity. Storage heights need to be maintained at a level that the sprinkler system is equipped to handle.
- Sprinkler heads blocked
- Sprinkler system is turned off. Credit cannot give credit to a system that is not operational.
- Unsprinklered areas, including the space below roll-up doors and canopies, spray booths, below raised floors, walk-in coolers, office additions and attic space.
- Inadequate water supply. The sprinkler rating depends on the water supply available to keep the system flowing. Many designs have pumps and tanks or both to supply water. Most systems rely on municipal water for supply. In each case the supply has to be tested and documented in order to provide the credit for the system and, more importantly than that, the actual water to extinguish the fire.
Building fire sprinkler systems are complex tools designed to fight fire to save lives and protect property. If they are maintained properly they can mean all the difference in the rare chance they are needed. It's vital to have a professional examine and test the system each year and to document the results.