August 1993 Infoletter
Summary: The following article is a part of the National Board Classic Series, and it was published in the National Board BULLETIN. (3 printed pages)
The article below, originally published in the August 1993 National Board Infoletter, was written to aid in the recovery of boiler systems affected by flooding.
After the waters recede, people will begin the long process of cleaning and restoring their property. The following information is provided to assist in recovery of boiler systems affected by the flooding.
- Safety of the personnel performing inspections and repairs is the highest priority. Flood waters contain many hazardous chemicals and bacteria, therefore personnel safety procedures should be developed and enforced.
- All utilities in the boiler room should be turned off until inspection and necessary repairs of the individual systems allow reactivation.
- A careful visual inspection of the entire boiler system should be made, both internal and external, with notations of obvious problems and any special equipment or personnel needed to facilitate repairs.
- Keep in mind that some equipment may only be repaired by the original manufacturer or its licensed agents in order to maintain warranties and/or certification.
- The boiler setting or foundation should be examined closely to determine if it has been weakened or undermined. Any movement of the boiler or building will have an adverse effect on piping and other equipment connected to both the boiler and building structure.
- Waterlogged insulation will hasten external corrosion of boilers and pipes. If removal is deemed necessary, remember that asbestos is still present in many boiler rooms and requires handling by specially licensed personnel. If the 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 to the external lagging.
- Refractory and fire brick should be checked for deterioration or loosening.
- Feedwater and condensate return systems should be thoroughly cleaned of any mud, silt or debris. After the boiler is put back in operation, the water quality should be checked often for contamination of any kind.
- Pressure relief devices should be checked for corrosion or any damage which could cause binding and failure to operate. Only qualified personnel should perform disassembly or repair of a pressure relief device. Some jurisdictions require this work to be performed by a company holding the National Board "VR" symbol stamp. The outlet and discharge line of the pressure relieving device should be inspected for blockage.
- All drains and blow-off lines should be inspected to ensure there is no blockage by debris.
- Electric/electronic controls should be evaluated for replacement or repair as needed. Flame safeguard controls, ignition transformers and safety shut off valves on the fuel system which have the potential for causing furnace explosions should be replaced. Other fuel system components should be drained and cleaned or replaced as necessary. All work performed on the fuel system and safety devices must comply with jurisdictional requirements.
- All electric motors and wiring should be inspected closely to determine if repair or replacement is necessary. All electrical work must comply with jurisdictional requirements.
- Check to make sure air inlets and exhaust stacks are clear of any blockage and are not damaged.
The items listed above are not intended to be all inclusive, since boiler systems and equipment vary in design and operation. However, this list could be used as a catalyst to developing individual inspection and repair guidelines to fit many systems affected by the flooding.
This article was inspired by information obtained from various sources. We would like to acknowledge The Locomotive, published by Hartford Steam Boiler Inspection and Insurance Company, and the National Board technical staff.
Editor's note: Some ASME Boiler and Pressure Vessel Code requirements may have changed because of advances in material technology and/or actual experience. The reader is cautioned to refer to the latest edition of the ASME Boiler and Pressure Vessel Code for current requirements.