Chapter 8Specialized Water-Based Fire Protection Systems

Objectives• State three reasons why, under certain

circumstances, the installation of specialized types of water-based fire protection systems is a better choice than standard automatic fire sprinkler systems.

• Discuss the characteristics and applications for fixed foam systems.

Objectives• Discuss the characteristics and

applications for foam-water sprinkler and foam-water spray systems.

• Discuss the characteristics and applications for water spray fixed systems.

• Discuss the characteristics and applications for water mist systems.

Objectives• Discuss the inspection and test

requirements for acceptance of specialized water-based fire protection systems.

• Recognize the possible impairments to specialized water-based fire protection systems.

Introduction• There are several

specialized water-based fire sprinkler systems.– Low-, medium-, and high-

expansion– Compressed air– Foam-water sprinkler and

spray– Water spray fixed– Water mist

• Specialized types of water-based systems are typically installed to protect special hazards.

• Both model building codes permit the use of alternative suppression systems.

Types of Specialized Water-Based Fire Protection Systems

• Fixed foam systems– Accomplish protection objectives for

target:• Flammable/combustible liquid facilities• Petroleum refining/ storage/dispensing

facilities– When properly applied:

• Smother fuel to isolate ignitable vapors• Isolate or separate fuel from fire• Cool fuel and surrounding area

© A. Maurice Jones, Jr./Jones & Bartlett Learning

• Foam is less dense than fuel or water and will flow freely over liquid.

• Fixed foam systems have a proportioner, foam concentrate tank, foam distribution equipment, and a pump.

• Compressed air foam systems combine air or nitrogen, water, and foam concentrate in correct proportions.

© A. Maurice Jones, Jr./Jones & Bartlett Learning

Types of Specialized Water-Based Fire Protection Systems

• Foam-water sprinkler and foam-water spray systems– Foam and water as companion suppression

agents– Protect Class B and some Class A hazards– Primary design goal is to extinguish the fire.– Specialized heads or nozzles may be used.– Design and installation standard is NFPA 16.

Types of Specialized Water-Based Fire Protection Systems

• Water spray fixed systems– Fixed piping networks with

specialized spray nozzles– Designed for fire control,

prevention, extinguishment, or exposure protection

– Require adequate automatic water supply

– Ultra-high-speed water spray

© A. Maurice Jones, Jr./Jones & Bartlett Learning

Types of Specialized Water-Based Fire Protection Systems

• Water mist systems– Fixed systems that discharge a

very fine-spray mist of water droplets

– Protect land facilities and offshore facilities and equipment

– Total flooding, local or zoned application

– Single- or twin-fluid systems– NFPA 750

Courtesy of Tyco Fire Protection Products

Types of Specialized Water-Based Fire Protection Systems

Inspection, Testing, and Maintenance Requirements

• Overview– Similar processes as standard fire sprinkler

systems– Failure to perform the various inspections

could lead to system malfunction.– All systems are subject to the same

acceptance inspections and tests.– Tests are generally consistent with standard

fire sprinkler system requirements.

Inspection, Testing, and Maintenance Requirements

• Periodic inspection, testing, and maintenance– Same types of impairments as primary water-

based systems– Foam and water mist systems require

additional periodic flushing. – A plan should be in place to work around the

impairment.

Summary• Specialized water-based fire protection

systems include low-, medium-, and high-expansion foam systems, water spray fixed systems, foam-water sprinkler systems, foam-water spray systems, and water mist systems.

Summary• Specialized water-based fire protection

systems provide protection to hazards where automatic fire sprinkler systems would not be appropriate for the conditions and applications, where there is a need for a supplemental suppression agent or different suppression agent, or where the method of application requires specialized equipment and components.

Summary• In many ways, specialized water-based fire

protection systems are similar to the four most prominent types of automatic fire sprinkler systems. However, the noted differences include the use of specialized spray nozzles and discharge devices instead of fire sprinkler heads, the integration of foam agents with water to protect certain hazards, the use of specialized components for the application, and the design and application methods.

Summary• Foam systems use different types of foam

to protect hazards where two-dimensional (surface) fires are possible. These systems also protect facilities that store large quantities of ordinary combustible materials, including petroleum refining, storage, and dispensing facilities; tank farms; chemical plants; aircraft hangars; power plants; and rolled-paper storage facilities.

Summary• Water spray fixed systems protect equipment such

as electrical transformers, oil switches, motors, cable trays, paper, wood, textiles, flammable liquid and gas materials, and certain hazardous solids.

• Foam-water sprinkler or foam-water spray systems protect flammable and combustible liquid hazards including aircraft hangars and petroleum dispensing and storage facilities. These types of systems are also acceptable for use with certain Class A hazards.

Summary• Water mist systems protect land facilities

including computer rooms, telecommunication equipment areas, laboratories, data centers, tunnels, underground mass transit systems, industrial machinery, electrical switchgear rooms, archives and storerooms, transformer areas, aircraft hangars, aircraft cargo spaces, museums and historic buildings, hotels, commercial buildings, and food processing areas.

Summary• All of the water-based fire protection

systems go through a similar acceptance testing process to ensure the system is ready to operate and perform as designed.

Summary• Periodic inspections, tests, and

maintenance provide verification that the system is capable of performing as designed and the conditions of installation have not changed in such a way that the system will not operate and perform as installed. Servicing and maintaining systems at the prescribed intervals will help to reduce and avoid system impairments.