By PAUL BARRA, chief engineer, and KAREN CAULFIELD, underwriting manager at Liberty Mutual Property
With the approach of the Winter Solstice, building managers in most parts of the country have brought their heating systems on line. This change brings with it both the seasonal tenant tug-of-war over preferred temperature levels and the constant inspection, testing and maintenance needed to keep the heating system up and running.
Damaged boilers can cost upward of $50,000 to repair, and, depending on boiler size and the scope of damage, the work can take anywhere from five to 60 days to complete. This indeterminate repair time may necessitate procurement of an alternative heat source to maintain building operations--at significant expense. For example, rental boilers brought in to maintain building heat and hot water require a monthly fee in addition to any costs associated with their installation. However, if the building is uninhabitable due to lack of heat and hot water, and the use of a rental boiler is not feasible, building occupants may need to be moved to an alternate facility until repairs are completed.
A building owner could be responsible for these additional expenses including any resulting business income loss and continuing expenses associated with the uninhabitable building.
While an expanded equipment breakdown insurance policy could provide business interruption and
extra expense coverage to pay for these indirect expenses, the hassle of dealing with damaged equipment and the possibility of losing customers and goodwill still remain.
In addition to handling the day-to-day operation of a commercial property, building managers are responsible for keeping operations compliant with a wide range of state and federal laws and building codes. Among these are the codes and laws established by the Authority Having Jurisdiction (AHJ) governing construction, installation and operation of boilers.
All 50 states have separate laws and rules governing boilers, with some more stringent than others, and building owners are responsible for ensuring their equipment conforms with all of the requirements of the local AHJ.
Additionally, all states have adopted the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessels Codes of Construction that boiler manufacturers must adhere to and the National Board of Boiler and Pressure Vessel Inspection Code that inspectors and repair firms must follow. All AHJs also have other requirements that may be unique to their jurisdiction and could include exemptions to their requirements due to size, use or type of equipment as well as the adoption of other codes and standards.
To ensure their equipment meets all of the appropriate codes and laws, building managers should only employ qualified service technicians who follow the manufacturers' instructions and recommended practices for installation. Managers should also keep the area around boilers free of obstruction and maintain clearances to meet code requirements, as well as provide access for inspection, servicing and repairs.
PREVENTING BOILER FAILURE
One of the most common causes of boiler failure is overheating due to a lack of water inside the boiler. Water in the boiler serves a dual purpose--extracting heat from the fuel to heat the building and keeping the metal surfaces in contact with the flame at a low temperature so they do not overheat, become weak and fail.
To ensure that the boiler retains an adequate amount of water, both steam and hot water boilers have a low water fuel cutoff (LWCO) safety control device that shuts off the fuel when water in the boiler drops below a predetermined safe operating level. A LWCO can be either a standalone unit or a multifunctional unit that is equipped with other controls such as a lock out and manual reset device, an automatic make up feed water valve or a feed water control.
Two common types of LWCOs are the float and the probe and either can be used for steam or hot water applications. Typically float types are used on steam boilers and probe types on hot water boilers.
The float type LWCO consists of a casting that houses a chamber where a float mechanism actuates an electric switch at a preset level to enable or disable the fuel firing system. It works in the same way as a toilet bowl float controls the water level in the tank. The probe type LWCO uses a metallic rod, or electrode, that is inserted into the boiler water at a preset level. When the water is in contact with the probe an electrical circuit is completed and the fuel firing system is enabled. When the water level falls below the probe and is no longer in contact, the electrical circuit is opened and the fuel firing system is disabled.
LWFC TESTING, INSPECTION AND MAINTENANCE
As with any mechanical or electrical device, LWCOs require regular maintenance and testing to ensure proper operation. Some typical problems encountered with float and probe type LWCOs include:
-- Faulty installation that results in the unit not functioning as intended
-- Jumper wires that render the unit inoperable by bypassing the electrical circuit that shuts down the burner and fuel system when a low water condition exists
-- Accumulation of sludge and sediment in the float chamber that prevents movement of the float assembly with water level fluctuations
-- Collapsed, bent or punctured float assemblies that inaccurately reflect true water level
-- Sludge and scale encrusted probes or electrodes that complete the electrical circuit without water being present
-- Corroded, bent or broken probes or electrodes that operate at a false water level
Building managers can head off these problems through:
-- Installation and maintenance of equipment by qualified technicians who follow the manufacturer's instructions and code requirements
-- Periodic inspection of controls and control panels for any modifications
-- Periodic float chamber flushing by qualified technicians to remove sludge and sediment
-- Maintaining boiler water chemistry within the limits set by the manufacturer or water treatment consultant
-- Annual disassembly and inspection to ensure the unit is intact (All the plugs on cross tees should be removed during any inspection of the LWCO.)
-- Periodic testing, disassembly and inspection of probe devices and circuits to ensure they are intact and operating as intended
During any LWCO testing, the burner must remain operational in order to verify shutdown when the water level reaches the preset low point. Common testing techniques include:
-- The quick drain test simulates low water conditions and should be performed weekly on float type devices for both steam and hot water boilers. For hot water boilers, a means to temporarily isolate the device must be provided during this test that automatically returns it to its normal position. Without the temporary isolation, the entire hot water system would drain before the LWCO functioned. By opening the drain valve on the bottom of the float chamber, the float will drop in the chamber, open the burner control switch, and shut off the burner and fuel system.
-- The slow drain test is performed on steam boilers and results in a gradual loss of water level that would reflect actual operating conditions. This test requires two qualified technicians and should be performed annually. This test is not suitable for hot water boilers, as it requires draining the entire system.
While the boiler is in operation, the feed water is shut off and one technician slowly opens the boiler drain valve while the other technician watches the water level closely as it drops in the gage glass. The burner should shut off before the water reaches the lowest visible level in the glass, the drain valve should be closed and the water level returned to its normal operating level. The burner will then restart. If the burner does not shut off, the drain valve should be closed, the water level restored to normal and the boiler shut down until the LWCO is functioning properly.
-- Probe type LWCOs can be tested weekly by activating a test switch on the device. This test verifies that the loss of the circuit created by water covering the probe will shut down the burner and fuel system.
While boilers require a lot of maintenance to be reliable, the money spent on hiring qualified technicians who work on the system is far less than what would be spent if a boiler breaks down. By using all available sources of information--including their insurers and brokers--building managers can strive to remain compliant with local AHJ regulations and stay open for business.
December 1, 2009
Copyright 2009© LRP Publications