Considering the potential danger of boilers and water heaters, it is important to know what warning signs to look for in the aftermath of a natural disaster.
An overheating water heater can quickly be identified by steam or a mixture of steam and water being discharged at the safety relief valve or from an open hot water faucet. If this condition is found at the faucet, close the faucet. In both cases, immediately shut down the water heater’s source of heat. Allow the water heater to cool naturally without the addition of cold water. Contact a qualified repair firm to investigate and correct the cause of the overheating before attempting to use the water heater again.
An overheating boiler may exhibit one or more of the following conditions:
1. A discharging safety relief valve.
2. Pressure and/or temperature readings above the maximum allowed for the boiler.
3. Low or no water in boilers equipped with water-level gage glasses.
4. Scorched or burning paint on the boiler skin casing.
When a water heater or boiler is overheating, the only safe intervention is to REMOVE THE HEAT SOURCE BY STOPPING THE SUPPLY OF FUEL OR AIR, and in the case of electrically heated units, to turn off the electric power to the unit.
1. Do not try to relieve the pressure.
2. Do not add water into the vessel.
3. Do not try to cool the vessel with water.
Get away from the vessel and let it cool naturally. Remember, the equipment can be a potential bomb. At this point, the best thing to do is to call a qualified repair firm. A jurisdictional authority will be able to provide a list of qualified organizations.
When recovering boilers after a flood, there are several items to keep in mind during the cleaning and restoration process.
1. Flood waters contain hazardous chemicals and bacteria, so the safety of those aiding in cleanup and inspection must be enforced.
2. Some equipment may only be repaired by the original manufacturer or its limited agents in order to maintain warranties and/or certification.
3. The combination of water and mud can adversely affect every aspect of the boiler system. A thorough check including the foundation, refractory and fire brick, drains, blow-off lines, electronic controls, electric motors, wiring, air inlets, and gas stacks should be made.
4. Waterlogged insulation will hasten external corrosion of boilers and pipes. If removal is deemed necessary, keep in mind that asbestos is still present in many boiler rooms and requires handling by specially licensed personnel. If insulation is left in place and the boiler is fired before thoroughly drying, steam can be generated within the insulation layers thereby creating the potential for explosive damage.
5. Pressure relief devices should be checked for corrosion and damage as well. Some jurisdictions require any repair work to be performed by a company holding the National Board "VR" symbol stamp. Only qualified personnel should perform disassembly or repair of a pressure relief device.
Should a boiler or pressure vessel accident occur, it is equally important to know who to call as it is to know what to do. There are more than 50 chief boiler inspectors representing jurisdictions throughout the United States and Canada who are members of the National Board of Boiler and Pressure Vessel Inspectors. Calling one of these individuals will ensure the accident scene is thoroughly investigated by someone specifically trained in boilers and pressure vessels.
Keep in mind that boiler and pressure vessel accidents are rarely caused by a natural disaster. The conditions that result, however, can have devastating consequences.
Most accidents are caused by improper maintenance or improper operation. Many jurisdictions require inspections of boilers and pressure vessels in other than residential settings. However, some boiler and pressure vessel owners do not comply with the jurisdictional regulations.
Typically, insurance companies require regular boiler or pressure vessel inspections before insuring or continuing policies on units. A certificate indicates that a unit has passed inspection. Note the unit identification number on the certificate. This will be needed by the jurisdictional official for locating and identifying the unit.
Knowing the warning signs of potential danger resulting from damaged or overheated boilers and water heaters is but one portion of an effective contingency plan. The second, and perhaps more important element is knowing who to call when spotting a potential problem and knowing what to do. The following graph is a safety checklist that should be followed whenever boilers and/or water heaters are affected by natural disaster.
Boiler or Hot Water Heater Safety Checklist
1. Exterior shell and/or insulation. Look for indications of overheating.
2. Leaks. Look for water on the floor. Check for water or steam escaping from any part of a pressurized system including the boiler, valves, or piping.
3. Flue gas leaks. Look for black dust (soot) around sheet metal joints. Check all parts of boiler enclosure and breaching, especially in the connection of the stack.
4. Controls. Look for open panels, covers, and signs of rewiring on floor or bottom of panels. Check for jumper wires and locked shut-offs.
5. Electrical. Ensure that covers are installed on over-limit switches, temperature sensors, and controls.
6. Safety Valves. Ensure that a safety valve is installed with full-sized discharge piping properly supported and directed to a point of safe discharge. Safety valve set pressure must be equal to or less than boiler maximum allowable working pressure. Safety valve relieving capacity must be equal to or greater than boiler output.
7. Fuel sources. Check for the ability to shut off the fuel source to the vessel.
8. Gauges. Make sure temperature and pressure gauges are operational and located for proper monitoring.
9. Proper Piping. Check for proper supports and allowance for expansion and contraction.
10. Operating certificate. Observe certificate noting last date of inspection and expiration date when required.
Information provided by The National Board of Boiler and Pressure Vessel Inspectors, The Ohio Department of Industrial Relations, Division of Steam Engineers, and The Locomotive, published by Hartford Steam Boiler Inspection and Insurance Company.
John Hoh is the Assistant Director of Inspections for the National Board of Boiler and Pressure Vessel Inspectors.