Water spray systems design

Fixed water spray systems designed on an area coverage basis may also be used to wet/cool structural steel supports. In this case, the placement of discharge nozzles should be close, usually within 4 ft (1.2 m) of the steelwork being protected. Alternatively additional nozzles or a separate system may be provided. 

Water spray systems designed and installed in accordance with NFPA 15... 

Unless consideration of these factors indicates otherwise, NFPA 850 recommends that any oil-insulated transformer containing 500 gal (1,893 I) or more of oil be separated from adjacent structures by the distances in Table 8-20. If separation can not be obtained, then either a fire barrier or water spray system designed for 0.25 gpm/ft (10.2 Ipm/m ) should be provided. 

Automatic equipment promptly detected the hazardous vapor and operated the automatic high-density water-spray system, which was designed to wash the ethylene from the atmosphere. The leak was too large for the spray system to handle. 

An active fire protection system requires some action to occur before it functions per its design intent. This action may be taken by either a person or control system. Examples of active fire protection systems are monitors, water spray systems, foam systems, emergency isolation valves, and ESD systems. 

For example, if LPG vessels are considered to be within a fire-scenario envelope, they require fireproofing unless protected by a fixed water spray system. API Standard 2510, Design and Construction of Liquefied Petroleum Gas Installations (API, 2001) recommends fireproofing pipe supports within 50 ft (15 m) of the LPG vessel, or within the spill containment area. 

A deluge sprinkler system is a sprinkler system designed to NFPA 13 with open sprinkler heads. A water spray system is hydraulically designed with open spray heads to protect a specific hazard. Water spray systems are discussed in Section 7.4.8. 

The design densities to be used in designing water spray systems are given in Chapter 8. 

The design of water spray systems should be in accordance with NFPA 15. Highlights and exceptions to NFPA 15 are ... 

The fire flashed back to the sphere surrounding it with flames. The water spray system for the sphere was designed to deliver only half the quantity of water normally recommended, and the supply was inadequate to meet the fire demand. The firefighters believed the relief valve would protect the vessel and so any available water was used to cool the neighboring spheres. 

This example examines the design of a water-spray system that is used for the mitigation of anhydrous ammonia in the event of an accidental release. The NH3 tank is capable of storing 35 m3, it is 11 m in length and is cylindrical in shape lying in the horizontal plane. The base of the tank is surrounded by a protective dike or a bund. All piping connections are at the bottom of the tank. This is shown in Figure 4.4. 

The water spray system must also be designed to ensure that water does not come in contact with live electrical equipment. Adequate clearances should be maintained under all anticipated weather conditions. 

As with all water-based extinguishing systems, there are temperature considerations associated with water-spray systems. In cold climates where freezing is a potential problem, selection of a water-spray system should not only be based on potential benefits, but also on the possibility of reliability problems. Care should be taken in the design to ensure that the... 

In this section we will demonstrate the use of water sprays as a postrelease mitigation measure. The theory and design of water spray systems has been detailed in Chapter 4. The scenario will involve the accidental release of hydrofluoric acid (HF) from a storage tank. Again we will be considering the distance to reach the ERPG-2 concentration for HF of 20 ppm (AIHA, 1992). 

Maddison, T. E. 1989. The Fire Protection of LPG Storage Vessels. The Design of Water Spray Systems, LPGITA Seminar, U.K. October. 

Waterwash spray booth. A spray booth equipped with a water washing system designed to minimize dusts or residues entering exhaust ducts and to permit the recovery of overspray finishing material. 

Are all fire water spray-system modifications being designed (including flow calculations) and installed by qualified personnel or contractor ... 

Shearer-Clearer A poorly designed external water spray system on the shearer body can actu-aUy raise operator dust levels. Poorly designed systems have nozzles directed upwind at the cutting and loading zone of the intake-side drum. Airflow generated by these sprays pushes dust away from the face and upstream of the drum. Here, dust mixes with the clean intake air and is carried out into the walkway over the shearer operators. 

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