Guide to choosing the right fire sprinkler

09/09/2022

Selecting the right fire sprinkler head is critical to the success of an automatic fire sprinkler system in controlling or extinguishing a fire. Sprinklers should be selected by assessing the usage, hazards and conditions such as (ceiling height, building type, ambient temperature, available water supply, etc.) and more specifically the area where the nozzles work

On the surface, sprinkler are designed to be very simple, but a lot of research and production classify them according to NFPA 13 standards for sprinkler system installation in many ways, including temperature ratings, coefficients K, injection direction, reaction type, design and performance characteristics, special service conditions. Some sprinklers are designed to protect storage facilities, and some sprinklers are designed as special application sprinklers.

Hướng dẫn chọn đầu phun sprinkler chữa cháy phù hợp

Hướng dẫn chọn đầu phun sprinkler chữa cháy phù hợp

Instructions for choosing a suitable fire sprinkler head include 02 separate parts as follows:

1. In Part 1 we will introduce to you the basic concepts of Sprinkler spray systems, temperature and K factor, so soon I will explore this article with you. - Basic concepts of Sprinkler Nozzles

- Sprinkler are one of many components that make up a fire sprinkler system. The piping system, including the water pipes to the building, the water pipes, the main pipes, the cross main pipes, and the sprinkler branch lines, together with the associated valves, fittings, and joints, make up the system. Water distribution supplies water to sprinkler heads. Is the final ingredient needed to effectively release “water” to control or extinguish a fire.

- A sprinkler “head” consists of a cast or forged metal frame with an integral orifice or drainage hole at one end and a water deflector at the other end. A temperature-sensitive mercury bulb, or heat element, is mounted in the frame to keep the hole covered and prevent water from draining out of the sprinkler. In the event of a fire, when the mercury ball reaches the limit temperature, it will explode and activate the firefighting water pump system to help prevent fires promptly.

- Choose the appropriate temperature

- To select the appropriate temperature rating for a sprinkler, one must be careful to match the sprinkler's temperature rating to the maximum expected ceiling temperature to avoid inadvertent discharge, Temperature rating, distribution Color-coded categories.

- Additionally, FM Global Data Sheet (FMDS) 3-26, Fire Water System Installation Needs for Nonstorage Sprinkler Properties, requires the use of high-temperature water sprinklers for all dry pipe systems in Section 2.1.1.1.

- K-Factor

- K coefficient is a mathematical constant set by the sprinkler head manufacturer related to the water flow discharged from the sprinkler at a certain pressure. When water is discharged through the sprinkler head, the diameter of the hole and the hydraulic characteristics of the hole determine the flow achieved through the sprinkler at a given pressure. An increase in sprinkler K-factor corresponds to higher flow rate (gpm) at a given pressure, and a decrease in K-factor corresponds to lower flow rate at a given pressure.

- K coefficient can be selected based on water supply characteristics. For supplies with higher available water at lower pressures, higher K-factor nozzles may be used. For water supplies with lower volumes of water available at higher pressures, a smaller K-factor nozzle may be used.

- Additionally, global data sheets NFPA 13 and FM 2-0, 3-26, and 8-9 specify the appropriate K-factor, minimum operating pressure, and number of sprinkler heads (or design area ) is calculated for each applicable design criterion. NFPA 13 further stipulates that (minimum) K = 8.0 sprinklers must be used to protect storage with a density of 0.20 or greater, and (minimum) K = 11.2 sprinklers must be used to protect warehouses with a density of 0.34 or greater.

- In Part 1 of the Guide to choosing the right fire sprinkler head, we shared the basic concept of fire sprinkler heads, choosing temperature and K factor. In Part 2, we will share nozzle direction, reaction type, design and performance characteristics as well as special types of nozzles.

- Spray nozzle orientation

- In general, sprinklers are manufactured to be installed in five basic directions: upward, downward, inclined, oblique wall, and ceiling. - Upward sprinklers are installed with a deflector above the frame so that water flows upward from the opening, hitting the deflector to create an umbrella spray pattern.

- Wall sprinklers are installed with a deflector below the frame so that water flows down from the water pipe opening, hitting the deflector to create an umbrella-shaped spray pattern.

- Horizontal Sidewall sprinklers are installed on the wall near the ceiling. The deflector is oriented parallel to the roof/ceiling and provides a quarter-sphere outward water spray pattern.

- Recessed Sprinklers are installed with all or part of the body mounted in a recessed box.

- Concealed sprinklers are installed with the entire body mounted in a recessed housing with cover to conceal the sprinkler.

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- Reaction type (Thermal sensitivity) - In general, there are two thermal sensitivities (rapid response and standard response) that measure how quickly the heating element operates once the air surrounding the sprinkler has reached the sprinkler's operating temperature. This is a measure of the operating element's thermal hysteresis. - Fast response thermal element has a response time index (RTI) of 50 (meter-second 1/2 ) per NFPA 13 (2016). Residential sprinklers, quick response (QR) sprinklers and early suppression rapid response (ESFR) sprinklers all have quick response thermal elements. - Standard reactive thermal element has an RTI of 80 (meter-second) 1/2 per NFPA 13 (2016) - Design and performance features - Nozzles are also classified according to their design and operating characteristics. Can provide fire control for a wide range of fire hazards.

- Controlled Density/Area Mode (CDMA) sprinklers are a type of sprinkler sprinkler intended to provide fire control in a variety of hazard types and configurations using density/area criteria. design area.

- Control Mode Specific Application Sprinkler (CMSA) is a type of sprinkler head that can produce characteristic large water droplets and can provide fire control for fire hazards has high difficulty.

- An early suppression rapid response (ESFR) sprinkler is a type of rapid response sprinkler that has a rapid response thermal element with an RTI of 50 (meter-second) 1/2 or less and can provide Extinguishing high-risk fires

. - An expansion nozzle is a type of nozzle that has a larger maximum coverage area but is more limited in distance than a standard reaction nozzle.

- Open sprinklers are sprinklers that do not have a heating element covering the drainage hole.

- A quick response (QR) sprinkler is a type of sprinkler that has a rapid response heating element with an RTI of 50 (meter-second) 1/2 or less and is listed as a quick response sprinkler for this purpose. intended use.

- A residential sprinkler is a type of quick-response sprinkler that has a quick-response heating element with an RTI of 50 (meter-second) 1/2 or less and has been specifically researched for its ability to enhance Survive in a fire room. origin, and listed for use in protecting residential units.

- Special service conditions

- Finally, sprinklers can also be classified according to the special service conditions they are designed to serve.

- Anti-corrosion sprinkler heads are made with corrosion-resistant materials, or with special coatings or plating, for use in environments that are typically corrosive to conventional sprinklers.

- Dry sprinklers have an extension knob that has a plug at the inlet to prevent water from entering the knob until the sprinkler operates, used in areas subject to freezing in cold environments

- Intermediate/cabinet-level sprinklers are equipped with an integral shield to protect the thermal element from electrical discharges of adjacent sprinklers installed at higher heights.

- In summary: Instructions for choosing a suitable fire sprinkler nozzle are only relative. When we want to use sprinkler nozzles effectively, choosing the right one is a condition for you to use them more effectively, less Costly for the project but still ensures fire safety.

 

>>> WHEN DO WE HAVE TO REPLACE THE SPRINKLER NOZZLE? >>>>

 

 

 

 

 

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