Valves fire safe

Procedures Spills, Leaks, Decontamination Process Isolation Block Valves, Fire-Safe Valves,... 

Install fire safe bottom valves Install fire safe valves on major solvent lines Install remote shut off of fuel sources Eliminate points of leakage (flanges, hoses). Replace with fixed/welded pipes Move flammable material storage away from vessel (e.g., pallets, etc.)... 

Use fusible link fire safe valves for automatic closure under fire conditions... 

New installations should be provided with only one connection below the liquid level, fully welded up to a first remotely operated fire-safe isolation valve located clear of the tank area. 

Valves. It is desirable and inherently safer to use fire-tested valves whenever it is necessary to isolate flammable or combustible fluids in a pipeline or tank or other type of equipment. Fire-tested valves were formerly called fire-safe valves. They were not really firesafe, and the name has been changed to fire-tested valves. Fire-tested valves should be considered for handling most fluids that are highly flammable, highly toxic, or highly corrosive and that cannot be permitted to escape into the environment. 

Construction materials should be selected that will withstand long-term exposure to the chemicals used in the process. This includes gaskets, which tend to be weak points in piping and vessels. Gaskets are discussed in Section V,E of this chapter. Occasionally fire-safe emergency valves are installed with gaskets that will quickly burn away if there is a fire. This tends to defeat the purpose of fire-safe valves. 

Fig. 8. Polyethylene tubing on fail-safe, spring-loaded, fire-safe valve used as an emergency block valve.

With the increase in popularity of automated plants, quarter-turn valves are very popular and are used in most installations. The only common quarter-turn valves that are available as completely fire-safe valves are ball valves and... 

Fire-Safe Valves that handle flammable fluids may have additional safety-related requirements for minimal external leakage, minimal internal (downstream) leakage, and operability during and after a fire. Being fire-safe does not mean being totally impervious to fire, but a sample valve must meet particular specifications such as American Petroleum Institute (API) 607, Factory Mutual Research Corp. (FM) 7440, or the British Standard 5146 under a simulated fire test. Due to very high flame temperature, metal seating (either primary or as a backup to a burned-out elastomer) is mandatory. 

The flare header, which collects the vapors from the safety valves for safe discharge to the knockout drum and the flare stack, is sized for the largest vapor load caused by a single failure. This vapor load is obtained from a tabulation of relief loads from safety valves connected to the flare system. The loads which may occur simultaneously as a result of fire, cooling water failure, etc., are summed up. From these summations the largest load is determined. 

Due consideration is also required on the potential role of SIF devices in mitigating damages when incidents do occur. External fires can often damage control valves or actuators, which are not designed to be fire-safe, and therefore cannot play a role in mitigating a fire after it has occurred. Separate fire-safe SIF isolation valves can be vital in mitigating such events. 

Overfill protection standards, paragraphs 73-78 Tank overfill protection, paragraphs 79-103 Fire-safe shut-off valves, paragraphs 104-114 Remotely operated shut-off valves (ROSOVs) paragraphs 106-109... 

Each pipe connected to a tank is a potentiai source of a major ieak. In the event of an emergency it is important to be able to safely isolate the contents of the tank. Isolation valves should be fire-safe, ie capable of maintaining a leak-proof seal under anticipated fire exposure. 

Fire-safe shut-off valves should be fitted close to the tank on both inlet and outlet pipes. Valves should either conform to an appropriate standard (BS 6755-2 or BS EN ISO 10497 ), equivalent international standards or be of an intrinsically fire-safe design, ie have metal-to-metal seats (secondary metal seats on soft-seated valves are acceptable), not be constructed of cast iron and not be wafer bolted. 

Dedicated export lines on bulk tanks containing petrol should ideally be fitted with fire-safe, fail-closed ROSOVs this would be the minimum expectation for a new tank installation. For existing installations, the need to provide ROSOVs retrospectively should be subject to an assessment according to the principles in FISG244. This assessment will need to include consideration of an individual having to enter a hazardous location to manually operate a valve for emergency isolation. 

Superseded Recommendation 3, 4, 5 - Fire safe shut off valves... 

Provide fire-safe or self-closing charging valves if required. 

Emergency isolation valves (EIVs) should be located based on two principles (1) the amount of isolatable inventory that is desired and (2) protection of the EIVs from the effects of external events. EIVs are normally required to have a fire safe rating (i.e., minimal leakage and operability rating) to a particular standard, e.g., API 607. Valves and their actuating mechanisms should be afforded adequate protection where they are required to be located in areas that have the potential for explosion and fire incidents. 

Installing a quarter turn fire-safe valve with a fail-safe mechanical spring actuator... 

EBVs used on tanks should be as close as possible to the tank flange and not in the piping away from the tank. In cases where EBVs may be exposed to fire, the valve and valve operating mechanism must be fire-safe. 

After the fire, the pump (and others) was relocated in the open air, under a canopy, so that small leaks would be dispersed by natural ventilation. It was surrounded by a steam curtain to disperse larger leaks. This would not have been necessary if the pump could have been located more than 150 m from sources of ignition. Gas detectors were installed to give early warning of any leaks. Emergency isolation valves (Section 7.2.1) were provided so that the pumps could be isolated safely from a distance [9]. What happened when another leak occurred is described in Section 7.2.1 (d). 

Depressuring devices may be used, but no credit for their use shall be allowed in sizing safely valves for fire exposure. 

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