Definition

• Sometimes a Siamese Connection is also called a Fire Department Connection (FDC)
• Siamese Connection / Splitter: A Y-shaped connection. It’s a double pipe fitting near the base of the building. Allows two hoses at the same time to connect to the standpipes and sprinkler system for the building to deliver pressure to a standpipe/sprinkler system.
• NFPA: National Fire Protection Agency

Introduction

Automatic sprinklers are normally required in high hazard areas , such as high rise hotels, vaults for storage of flammable materials, paint spray booths, hazardous parts of theaters, some types of garages, and certain hazardous basements.

Recently, more new construction has utilized sprinklers because property owners (and insurance companies) have discovered the benefits of life safety and reduced property damage by having a system in place. This has led to insurance companies offering reduced fire insurance premiums, and code writers to lessen restrictions if a sprinkler system is provided.

• For example, less exits may be required by code or certain evacuation distances can be increased. These are called “Trade-offs”.
• A developer who plans on selling a building soon after completion, may decide to save money by omitting sprinklers and leave the increased fire insurance premiums to a later owner.
• Buildings with sprinkler systems are sometimes referred to as ‘sprinkled buildings’

NFPA classifies buildings into 3 types of fire hazard: Light, Ordinary, and Extra. The hazard determines the sprinklers and location/quantity required.

Types of Sprinklers:

Wet Pipe

Most common system. 

1. The pipes are filled with water at all times. When the system reaches a trigger point by heat, it notifies the sprinklers to release water and the system responds immediately.
2. Triggered by heat, 135 to 170 degrees F is typically the trigger zone. This value varies based on existing temperature conditions within the ceiling.
3. When a sprinkler head opens, it typically triggers a FLOW DETECTOR which then sends a notice to the fire panel of where the fire is.

Dry Pipe

4. Typically used in areas that may be subject to freezing, like in sprinklers used for unheated warehouses or other unconditioned program areas.
5. The pipes are filled with compressed air or nitrogen until one or more of the sprinkler heads are activated. Water then rushes in to service the area.

Pre-Action

6. Similar to dry-pipe systems. When a sprinkler head is activated, the sprinkler head does not open immediately but rather there is a delay that allows firefighters to respond. 
7. This system is used where water damage is a concern and it’s worth waiting a little bit longer to fight the fire to see if it can be contained using less destructive methods.

Deluge

8. Used in high hazard environments where there is an extreme caution for fire safety
9. All of the fire sprinklers go off all at once, regardless of where the fire is detected.
10. Typically all of the pipers are kept empty and the heads kept completely open. A fire alarm will activate the valves which will send water to the entire system and therefore disperse it everywhere.

Supplying the Sprinklers

• In buildings, the supply will traditionally be from the public water main. 
• In tall buildings, the supply can be from a water tank at the top of the building, or from the water main. Sometimes both are utilized.

Sprinkler Heads & Covers

Older sprinkler heads use a fusible link, whereas new sprinkler heads have a glass bulb and liquid inside that is designed to break the glass and release. Based on the color of the liquid, it identifies the temperature it will break at.

Upright Heads

Sit above the sprinkler pipe and are used where the plumbing is exposed and ceilings are high and unfinished. Can be inexpensive as an option, and typically used in back of house and mechanical spaces.

Sidewall Heads

Used for corridors and small rooms where a single row of sprinklers can provide adequate coverage of the entire floor space. 

• Sidewall can be plumbed from walls instead of the ceiling, which makes them useful for remodel work

Pendant Heads

Located below the sprinkler pipe, this type of head is ‘pointing down’ and the most common for new built finished work.

• Recessed Head: partly recessed above the ceiling, with its deflector below the ceiling
• Flush Head: Has only its thermosensitive element below the ceiling.
• Concealed Head: has a smooth cover that is flush with the ceiling. During the fire, the cover drops off and then the sprinkler head activates. These can be finished to match the adjacent ceiling paint, but cannot be painted themselves.

Sprinkler Types

There are several different types of sprinklers. The type utilized will depend on the Occupancy Group, the contents of the space, and level of protection required.

Standard Residential Sprinklers: Fast response devices sensitive to both heat and smoldering

Quick-Response Sprinklers: More sensitive to heat than standard sprinklers, so they take less time to activate the sprinkler.

(ESFR) Early-suppression Fast-response: Sprinklers spray water at high pressure and at a higher rate of flow than most sprinklers and are for use in more hazardous locations.

• ESFR Sprinklers are designed to completely put out the fire while it is small. Other sprinkler types are just designed to keep the fire at bay while the fire department arrives to fight it.
• More sensitive to heat and produce larger droplets that penetrate fires better.

(QRES) Quick-response Early-suppression: Similar to ESFR, but have smaller orifices and are designed for light-hazard occupancies.

(EC) Extended Coverage: Sprinklers cover a larger area per head than most sprinklers, but they may be used only in light-hazard occupancies and under smooth flat ceilings.

Other Extinguishing Agents

Portable fire extinguishers are helpful for stopping small fires in the early stages of development.

• Four types of extinguishers, A through D, each used for a different purpose.

Intumescent Materials: Respond to fire by expanding rapidly, insulating the surface they protect and filling gaps to prevent the passage of fire, heat, and smoke.