FST 5 - Chapter 7 (automatic fire sprinkler systems)

Automatic sprinkler systems must go through an approval process to be accepted as a system that is ready to operate and perform as designed.

Acceptance Inspections and Tests Flushing Hydrostatic and air tests Visual inspection Operation of components

Attic sprinkler heads

Are installed at the peak of the attic

Institutional sprinkler heads

Commonly found in mental health, correctional, or detention facilities

Pipe and fitting joining methods

Commonly used joining methods i. Threads ii. Grooves iii. Flanges iv. Welds v. Solder vi. Heat fusion vii. Brazing viii. Pressure fittings ix. Glue

Ornamental sprinkler head

Covered with a factory-applied paint or finish that is usually requested by the architect, interior designer, or developer to achieve a certain look

Control-mode specific application sprinkler heads

Designed to control high-challenge hazards

Spray sprinkler heads

Designed to handle many different and challenging hazards

Early-suppression fast-response (ESFR) sprinkler heads

Discharge great amounts of water to penetrate strong updrafts and are designed to suppress a fire not just control it

Extended-coverage sprinkler heads

Discharge water over a greater area than a standard sprinkler head

Vertical-sidewall sprinkler heads

Distribute water like a sidewall head, but the head installation is in the pendent or upright position

Concealed heads

Installed above the ceiling and are hidden by a flush cover plate

Flush sprinkler heads

Installed flat or even with the ceiling with only the heat-sensitive components exposed

K-factor

K-factor establishes the mathematical relationship between the pressure and flow from a sprinkler head. (i) With Q being the discharge in gallons per minute, K being the discharge coefficient for the orifice of the sprinkler head, and P being the water pressure in pounds per square inch, the relationship for determining flow is expressed in the following formula: Q = K . (b) The K-factor also serves to classify the head, eliminating the need to refer to certain descriptors or types of heads.

Large-droplet sprinkler head

May be seen in facilities, but few manufacturers still produce heads, and NFPA 13 no longer discusses them

Residential sprinkler heads

Must operate substantially quicker than standard fire sprinkler heads

Types of sprinkler heads

Old-style heads (aka conventional heads) Standard spray heads Specialty heads

Other fire sprinkler standards

Other standards dealing with fire sprinkler systems are typically used in one of the following situations: a. When there is a level of hazard exceeding the scope of NFPA 13 b. When the standard has specific design requirements for the hazard c. When the approving authority requires the use of a different standard 2. These include NFPA 30, 30B, 214, and 804. 3. A few insurance providers develop their own standards for use at their clients' facilities. 4. The design professional must determine the best suited system to use. 5. In some instances, more than one standard may apply to a given facility, and the design professional will reference more than one of these to determine the best fire protection system design for a particular hazard or building.

Fire Sprinkler System Components

Pipe and Fittings Valves Pipe Support and Stabilization Assemblies Automatic sprinkler heads

Concealed-combustible-space sprinkler heads

Protect areas such as interstitial spaces constructed with combustible materials

On/off sprinkler heads

Protect areas where water damage is a great concern, such as a computer room or museum

In-rack or intermediate-level sprinkler heads

Provide protection within storage racks

Dry sprinkler heads

Recommended for environments where the temperature cannot be maintained at 40°F or higher

Corrosion-resistant heads

Specified for environments that promote corrosion

Pilot-line detector

Standard spray sprinkler or fixed temperature releasing device that either pneumatically or hydraulically releases the main sprinkler valve so water can flow into the system

Effectiveness in Life Safety

The purpose of a commercial or industrial fire sprinkler system is not necessarily to provide life safety, but to provide property protection. a. However, NFPA statistics show that when a wet pipe system is installed, there is an 87 percent reduction in fire deaths compared to in buildings that did not have a sprinkler system installed.

Valves

The valves should have a permanent metal or rigid plastic weatherproof sign identifying the area that the valve serves. (also valves must be indicating) All must be able to handle 175 psi or carry an appropriate rating for an anticipated pressure above 175 psi. 1. Check valves 2. Drain valves 3. Inspector's test valve (usually globe type or quarter turn valves)

Quick-response sprinkler heads

Use a thinner or less massive material for the heat-sensitive element than a standard response head

Open sprinkler heads

Used for deluge sprinkler systems and flow water from all heads over a large area without waiting for heat to activate them

Types of Systems

Wet pipe systems Limited area sprinkler systems Residential sprinkler systems Dry pipe systems Preaction systems Deluge systems

Automatic sprinkler heads

a. An automatic sprinkler head is a spray device that distributes water over a limited area at a designated flow rate. b. With few exceptions, sprinkler heads are heat-activated and operate at a predetermined temperature. c. Because each head operates independently, only the heads that reach the critical activation temperature will operate. d. Sprinkler heads should have a listing or approval obtained by the manufacturer through a recognized testing and certification agency such as UL or FM Global.

Residential systems do not require sprinkler heads to be installed in certain areas:

a. Bathrooms less than 55 ft2 b. Closets and pantries no greater than 24 ft2 and no more than 3 ft deep c. Garages d. Open attached porches e. Carports f. Attics g. Equipment rooms h. Concealed spaces

Design professionals classify the occupancy, commodities, or storage arrangement that the system must protect relative to the level of severity of a potential fire as a basis for most system designs. They determine the hazard by evaluating the following:

a. Combustibility b. Amount of combustibles c. Storage arrangement d. Rate of heat release of commodity, material, or product i. The system design must deliver enough water to absorb the energy from the fire so it does not grow any larger. ii. NFPA 13 establishes a number of hazard classifications based on occupancy, commodity, storage arrangement, and use of plastics, elastomers, rubber, and rolled paper storage. 3. They decide whether to use a pipe schedule for the design or hydraulically design the system. a. Very few pipe schedules are specified and few authorities accept pipe schedule designs unless they are tied to an existing pipe schedule system. b. Most design professionals choose to hydraulically calculate the system using density/area curves, which provide a graphic representation of the minimum amount of water that the system must provide at its most remote point. c. They consider modifiers and qualifiers. i. A design density applies only to areas of a building that meet the characteristics of the hazard group being referenced. ii. The square footage of a remote area increases by 30 percent when the fire sprinkler system is either a dry pipe or a preaction-type system.

Impairments to a fire sprinkler system result from the following:

a. Component failure b. Lack of proper inspection, testing, and maintenance 3. Many impairments are preventable and require only periodic inspection, testing, and maintenance to discover and correct.

Fire sprinkler head components (part 1)

a. Frame - Central component that holds the other pieces of the sprinkler head in place b. Heat-sensitive element - Released when the critical activation temperature is reached ii. Three common types (a) Glass bulb (frangible bulb) (b) Metal solder link (fusible link) (c) Solder or chemical pellet

Limited area sprinkler system

a. Installed to only protect a large storage area or basement of a building while the building itself does not require a full system installation b. Does not require a separate and dedicated water supply c. Is supplied with water from the domestic water supply for the building

Identification, labeling, and markings on sprinkler heads

a. Sprinkler identification number (SIN) i. Mandated in 2001 by the NFPA ii. Requires manufacturers to assign a unique character and number identifier to each head iii. Distinguishes operational characteristics from head to head iv. Eliminates the use of the traditional terms and identifiers discussed in the previous section v. Includes the manufacturer, the temperature rating, the type of head, the model number, the K-factor, the SIN number, and the listing or approval agencies

Wet pipe systems

a. The least expensive, most frequently installed, easiest to maintain, easiest to modify, and most reliable type of fire sprinkler system available b. Preferred to other types because water is in the pipes at all times, so water flow is immediate after a sprinkler head activates c. Should only be installed in environments that can be maintained at 40°F or higher to prevent damage from freezing d. Require a dedicated and automatic water supply e. Common in almost every type of building f. Usually have an alarm check valve or other flow-detecting alarm device i. To provide an alarm function to notify that water is flowing ii. To act as a check valve to hold pressure in the system and not allow the fire sprinkler water to flow back into the potable water supply iii. May be mechanical with a water motor gong or electrical with a retard chamber and pressure switch tied to an electric bell, fire alarm, or monitoring panel

The main observable differences of residential sprinklers compared to commercial sprinklers:

a. The piping, fittings, hangers, fasteners, and valves of a residential system tend to be smaller in diameter and size. b. Instead of steel, the primary piping materials are CPVC, copper, polyethylene, and polybutylene (in early systems).

Flushing (of incoming fire line)

i. A rate of 10 ft per second ii. Equal to or higher than the system demand rate iii. The maximum flow rate available to the system under fire conditions c. Flushing the line should continue until the water flow is clear.

Old-style heads

i. Also known as conventional heads and were the majority of heads until the early 1950s ii. Could be oriented to discharge water up and down, with 40 to 60 percent of the water initially flowing downward upon activation iii. Still being produced today but NFPA 13 limits the use to fur storage vaults and situations that require unique water distribution patterns

Many different types of fittings connect piping valves, sprinkler heads, and other components, including:

i. Elbows ii. Tees iii. Flanges iv. Crosses v. Unions vi. Couplings vii. Bushings viii. Plugs ix. Reducers d. Commonly used fitting materials are the following: i. Cast iron ii. Malleable iron iii. Wrought steel iv. Forged steel v. Wrought copper vi. CPVC

Standard spray heads

i. Emerged in the late 1950s and remain the most prominently installed head today ii. Can point in only one direction iii. Categorized by the orientation of the head relative to the way the water flows (a) Pendent—points down (b) Upright—points up (c) Sidewall—installs parallel to the ceiling or floor

Commonly used piping and tubing materials

i. Ferrous piping ii. Black steel pipe iii. Galvanized steel pipe iv. Copper tubing v. Alloy materials vi. Chlorinate polyvinyl chloride (CPVC) (dominant type used for residential installations) vii. Brass pipe

Hydrostatic tests for residential systems

i. For an NFPA 13 sprinkler, the hydrostatic test pressure should be equal to the water pressure of the system's source. ii. If the system requires a fire department connection, the test must follow the requirements of NFPA 13.

Hydrostatic and air tests

i. One of the most important tests performed during the construction phase ii. Requires pumping water into the sprinkler system to subject piping, fitting, valves, and other components to a predetermined pressure for a minimum time duration, usually 200 psi for 2 hours iii. If the system is a dry or preaction system, an air test is also required. (a) This test subjects the system piping to 40 psi of air pressure for a 24-hour period. (b) A maximum loss of 1½ psi is allowed over that period. iv. 200 and 40 psi are considered high ends of pressure exposure and therefore are good indicators of integrity.

Effectiveness in Property Protection

. The basis for fire sprinkler system design is to keep a fire at a relatively small size and under control, not necessarily to extinguish it.

NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes

1. First published in 1975, it addresses the residential fire problem by placing sprinklers in the areas of a home where a fire would most likely start, including: a. Kitchen b. Living room c. Bedrooms 2. Sprinkler head installation was excluded from small bathrooms, small closets, and unheated areas (attics). 3. The standard established that the system must: a. Be economically viable b. Provide sufficient time for escape or rescue c. Prevent flashover 4. Subsequent revisions to the standard relied on data to develop requirements for sprinkler heads designed specifically for residential applications.

Residential sprinkler systems

1. In order to protect property and protect life safety, these systems are designed to do the following: a. Prevent flashover in the room where the fire starts b. Improve the occupants' chance for rescue or escape 2. Manufacturers have gained approval to make dry pipe valves, but the vast majority are still wet pipe systems. 4. Many are supplied water by an appropriately sized domestic water line fed from a reliable community water system. a. Some have a specifically dedicated water line. b. Others are supplied by a stored water source with an automatically operated pump (systems used to protect smaller family dwellings). 5. Residential sprinkler heads must meet a different testing criterion than a standard fire sprinkler head. a. Must prevent the amounts of harmful fire by-products and associated temperatures from reaching levels that could inhibit rescue of or safe exiting by an occupant

Deluge systems

1. Operate in a manner similar to preaction systems a. Both require a fire detector activation or manual station release to open the system valve so water will flow into the pipe. b. The major difference is that these systems have open sprinkler heads without heat-sensing release before water discharge. i. Once water reaches the open heads, discharge is immediate and simultaneous from all of the sprinkler heads. ii. This arrangement provides large amounts of water over a predetermined area. 2. Operationally, the deluge valve receives the appropriate signal from the detection system to release the clapper. a. Electric method—Usually employs a solenoid valve tied to some type of detector that sends a signal b. Hydraulic method—Uses a wet sprinkler (pilot) line over the hazard area c. Pneumatic method—May use two different means of release: i. A dry sprinkler (pilot) line with closed sprinkler heads over the hazard area ii. A heat-activated device that ties to small-diameter copper lines 3. These systems usually protect high hazard occupancies. a. Power plants b. Aircraft hangars c. Woodworking facilities d. Explosive and ordnance factories e. Refineries f. Cooling towers g. Chemical storage or processing facilities 4. These systems commonly use foam as part of the suppression agent.

Pipe and Fittings

1. Pipe and fittings join together to provide a conduit for the water that flows to, and then out of, the fire sprinkler heads.

Dry Pipe Systems

1. Protect an area of a building where temperatures fall below 40°F 2. Can be used for unheated warehouses and attics, loading docks, parking garages, and commercial freezers 3. Instead of water, pressurized air (or nitrogen gas) is maintained in the system piping until the system activates and floods the pipe with water. 4. Systems must be installed where the incoming water supply, dry pipe valve, air compressor, and associated components stay in a heated and protected area to prevent water from freezing. a. The dry pipe valve is the key component to prevent water from entering the dry pipe system. i. Many dry pipe valves operate on an air-to-water differential (ratio) design principle. ii. For example, the air-to-water differential may be 1:5 where 1 pound of air pressure will hold back 5 pounds of water pressure. b. When one or more sprinkler heads activate to reduce the air pressure: i. The air-to-water ratio is disrupted. ii. The water pressure trips the dry pipe valve causing the clapper plate to swing off the set and latch in an open position. iii. Water flows into the pipe, pushing the air out until eventually reaching the open sprinkler heads. iv. Water also flows into a chamber in the dry pipe valve, and then flows out and triggers an alarm. 5. Systems may have accelerators or exhausters installed. a. An accelerator attaches to the dry pipe valve and senses system air pressure loss. i. When pressure loss occurs, the accelerator opens an internal exhaust valve to redirect the pressurized air to disrupt the differential and force the clapper to open and latch. ii. This is either mechanical or electronic. b. Exhausters can attach to the dry pipe valve or any location where there is 2-inch piping. i. They sense rapid losses of air pressure and open a port that purges air out of the system at a rate roughly equivalent to 15 open sprinkler heads. ii. Process allows the clapper to open more rapidly and removes air to accelerate the speed at which water fills the pipe. 6. Systems are more complex, in general, than wet pipe sprinkler systems, including the following: a. Installation and maintenance to prevent internal rust, scale, and corrosion b. Resetting the dry pipe valve

Pipe Support and Stabilization Assemblies

1. The majority of sprinkler piping runs horizontally across a building's ceilings. 2. Piping is held in place by the following: a. Bracing, guides, and restraints hold the pipe in position and prevent movement. b. Hanger assemblies consist of a fastener or clam, threaded rod, and a ring that holds the pipe. c. Fasteners secure the other components to the structure and must be the appropriate type. 3. With the exception of materials that passed fire tests and have a listing for the purpose, all hanger and supporting components must be made of ferrous materials, which can handle the heat of a fire better than aluminum or copper. 4. Hanger assemblies must be able to hold five times the weight of the water-filled pipe plus 250 pounds. 5. Spacing and location of the hanger components depend on the size and type of piping (determined by NFPA 13)-refer to page 150

NFPA 13, Standard for the Installation of Sprinkler Systems

1. The performance objective from the first edition (created in 1896) of the standard to the most current edition is to maintain control of a fire to the point that emergency responders can complete the suppression activity. a. Controlling the fire necessitates containing the fire to the general area of origin. b. Sprinkler heads should cover all spaces in the building, including: i. Concealed combustible spaces ii. Attics iii. In some instances, the space above and below ceilings 2. The same requirements and performance objectives apply to all occupancy, commodity, and storage conditions covered by the standard. a. Every system design establishes a minimum performance level for the occupancy based on an evaluation of the hazard. b. Although control of the fire remains the basis for NFPA 13, in many instances the sprinkler system is more than adequate to extinguish the fire before manual firefighting is necessary. i. Remains one of the most widely used NFPA standards

The Basis for the Design of an NFPA 13 System

1. The professional must determine three factors before the design can move forward: a. The hazard b. The design density required to protect the hazard c. The water supply necessary to support the system demand 2. When these are determined, the designer will provide the best system to control and extinguish a fire.

Automatic Fire Sprinkler Systems

1. These systems are networks of underground and overhead piping fed by automatic water supply. a. Upon activation, sprinkler heads connected to the piping at specific intervals apply water over a fire area. b. They have been used for over 130 years to protect property and provide life safety. c. They are unmatched in accomplishing the primary goal of controlling a fire. 2. Dispelling disparaging myths about these systems requires further education to the public about how they work. a. They are ready to operate without human interaction and thus are practical to use. b. The synthetic materials used for construction increase fuel load, burn faster, and emit toxic by-products. c. Properly installed and maintained smoke alarms will alert occupants that there is a fire. 3. Automatic sprinkler systems offer reliable, effective, economical, and proven protection for building and homeowners, including protection of: a. Valuables b. Property c. Lives of their family members, employees, and other occupants of the buildings

NFPA 13R, Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies

1. This standard addresses residential fire problems with occupancies such as hotels, motels, apartments, condominiums, and in some cases, large single-family dwellings that reach four stories. 2. It loosely follows NFPA 13 requirements, including: a. Installation of at least one fire department connection in buildings over 2000 ft2 or more than one story b. Sufficient water to support multiple sprinkler heads flowing simultaneously c. Design proved by hydraulic calculation d. Hydrostatic testing consistent with NFPA 13 requirements 3. It follows NFPA 13D concepts of placing sprinkler heads in areas where a fire is most likely to start. 4. The standard has evolved to deal with the technological advances and to offer clarifications to existing requirements.

Preaction systems

1. Use closed sprinkler heads (like dry pipe systems), and under normal conditions there is no water in the system piping a. May have low-pressure supervisory air in the piping b. Unlike dry pipe systems, release of the preaction valve is usually caused by fire detector activation. 2. Most require two separate events before water discharges: a. A fire detector must activate the preaction valve so that water flows into the piping, essentially making the system a wet pipe sprinkler system. b. A sprinkler head must activate to flow the water. 3. The preaction valve can be released by various activation methods: a. Hydraulic—Uses quick-response sprinkler heads on a wet (water-filled) pilot line to release the preaction valve b. Pneumatic—Uses quick-response sprinkler heads on a dry (air-filled) pilot line to release the preaction valve c. Electrical—Uses heat, smoke, or flame detectors interfacing with a fire control panel to release the valve 4. Operational arrangements provide progressively higher levels of certainty that there is a fire before water flows: a. Noninterlock—Follows requirement for two separate events to occur b. Single-interlock—Follows the requirement that a detector releases water into the pipes c. Double-interlock—Requires that both a detector and a sprinkler head activate before any water flows 5. Other operational features a. Activation of detectors in different zones before the valve releases the water (cross-zone detection) b. Use of low air pressure to monitor pipe integrity c. Use of higher air pressure to hold the preaction valve closed d. Pre-alarms, trouble alarms, and supervisory alarms to indicate a change in system status e. Manual release capabilities

Fire sprinkler head components (part 2)

c. Orifice - Smooth opening in the head through which the water flows from the pipe - The size of the orifice regulates the amount of water flow; it may be as small as ¼ inch or as large as 1 inch, depending on the water supply and available water pressure. d. Orifice cap—forms a tight seal that keeps the water from flowing until needed e. Deflector—breaks the water stream into smaller droplets and forms a relatively even distribution spray pattern f. Trim ring, cover, cup, or escutcheon plate - Appear to be only decorative but may be required as part of the listed assembly to meet the fire-resistive rating for the ceiling or wall g. Sprinkler head wrench—a tool designed to install or remove a sprinkler head

NFPA 25 - testing intervals

i. Weekly, monthly, quarterly, and semi-annual system inspections should be performed. ii. Annually, all systems should receive a complete visual inspection and operational test. f. Every 3 years, dry pipe systems require a full trip test. g. Every 5 years, a sample of extra high-temperature sprinkler heads needs to be tested. h. A sample of fast- or quick-response sprinkler heads requires testing initially after 20 years of service and then every 10 years thereafter. i. At 50 and 75 years of service, a sample of all sprinkler heads requires testing.