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Boiler Safety

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Boiler Basics (cont.)

Excessive Pressure Accidents: Excessive pressure is potentially the most lethal form of boiler accident. These accidents occur when the boiler can no longer contain the excessive pressure allowed to build in the boiler. The operator control, high pressure limit, and the pressure relief valve need to fail before these accidents can occur. Excessive pressure accidents, even in small boilers, have been known to completely destroy a building.

Fuel Related Accidents: Fuel related accidents usually occur when the operator fails to purge combustible gases from the fire box before ignition is attempted.

Leaking fuel valves can also be the cause of these accidents. If the operator notices any gas odor the boiler should be shut down and the fuel supplier called immediately.

Water Treatment Basics

Boilers are filled with water that contains naturally occurring impurities. Common impurities such as calcium, magnesium and oxygen can, if they are not controlled, effect boiler performance and durability.

All water contains dissolved minerals such as calcium and magnesium. If these minerals are allowed to reach high enough levels in the boiler water they will come out of solution and form as a hard shell on the hot surfaces of the boiler. This hard shell is called scale and is often found on the outside of the fire tubes. Scale insulates the heating surfaces reducing the ability of the fire tubes to transfer heat from the hot combustion to the boiler water. High stack temperatures or ruptured fire tubes are common problems related to scale build up.

Boiler water also contains dissolved gases such as oxygen or carbon dioxide. These gases in the presence of water and metal can cause corrosion. Corrosion eats away the metal effecting the durability of the boiler.

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