Temporary Boilers: Overview and Applications

Boilers are among the main sources of heat used in buildings and play a fundamental role in adapting interior spaces to human beings. However, boilers are vulnerable to component failures, like any piece of mechanical equipment, and disconnection may be necessary during building renovations or heating system upgrades. Temporary boilers can meet the heating needs of buildings in these circumstances. Please note that the New York City Department of Housing Preservation and Development requires space heating availability from October 1st to May 31st, and hot water availability year-round.

There are many possible scenarios in which a building could be temporarily without a boiler, and the following are some examples:

• Heating system fuel conversions , for example from No. 4 heating oil to natural gas. These projects can take 6 to 12 months to complete.
• Boiler repairs and component replacement.
• Damage to buildings due to extreme weather conditions.
• Chimney repair, replacement or installation of new lining.
• Reduction of asbestos in the boiler room, requiring the shutdown of all equipment.

There may also be temporary situations where heating demand is higher than normal, for example very cold winters. There are also healthcare applications where the supply of hot water is critical and must not be interrupted under any circumstances, requiring a backup system.

Renting a temporary boiler is an effective solution when heating production is urgently needed and the existing boiler is not available or has insufficient capacity. The cost of a temporary boiler is typically in the range of $5,000 per month, but the building can continue normal operation while its heating system is put back into operation or upgraded.

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Installing a temporary boiler is much quicker than installing a permanent unit, but project planning is still important. Depending on your location, there may be significant transit time due to the weight and size of the unit, and it must then be connected to your building. Operator training may be necessary, and also remember that the availability of temporary boilers may be reduced during emergencies such as winter storms.

Temporary Boilers and Code Compliance

Code compliance is a key challenge when deploying temporary boilers. Considering their important role in buildings and the risks associated with combustion, they are subject to strict requirements, despite being temporary. Code compliance can be planned in advance on a typical project, but time available is typically short when dealing with temporary boilers.

In 2012, Hurricane Sandy revealed how vulnerable New York City's buildings are to extreme weather events, leaving many properties without electricity and heat. The New York Department of Buildings and the New York Department of Environmental Protection have recognized the need to simplify the approval procedure for temporary boilers in emergency situations. The NYC DOB has amended its rules to allow installation prior to approval, subject to the following conditions:

The above procedure also applies to the temporary storage of fuel oil if necessary for a particular application. The approval process can be expedited by using the New York City Department of Buildings' electronic filing system.

When filling out the Emergency Work Notice, the installer must include the following information:

• Project address.
• Description of the emergency situation requiring temporary boiler and/or fuel storage.
• Licensed contractor information: name, license number, and phone/fax or email.
• Registration number of the existing boiler.
• LAA1 filing statement within 5 days and complete filing/approval within 60 days.

The New York Department of Environmental Protection must also be notified, and the information required is as follows:

• Project address.
• Make and model number of boiler and burner.
• Boiler input or firing rate in BTU/hour.
• Fuel type, only #2 heating oil and natural gas are allowed.
• Licensed contractor information: name, address and telephone number.

After notification is sent, the New York DEP assigns a facility number and provides a temporary work authorization. This permit expires in 30 days and a complete work permit application must have been submitted by then.

Temporary Boiler: Unit Features and Configurations

A temporary boiler has many features that make unattended operation possible, summarized below. Please note that some features are optional, used to improve performance or in special applications.

• Feed water replacement system: The water supply is essential for the operation of the boiler, since water is the means of transporting heat. A temporary boiler becomes much simpler to install if equipped with a feed water tank.

• fuel burner

• Steam pressure reducing valve (PRV): In buildings that use steam heating, this device allows the steam pressure to be adjusted according to the needs of the distribution system.

• Gas Pressure Regulator: Reduces compressed gas pressure if necessary by the boiler, as utility gas supply pressure varies by location.

• Chemical treatment device: Removes dissolved solids and gases from the supply water, increasing boiler efficiency and heat transfer.

• Expansion tank: Provides pressure relief.

• Pre-wired boiler control unit.

• Pre-tube relief valves.

• Water pumps: Primary and standby, dual supply.

• Chemical pumps: For injection of chemical additives, if required by the application.

• Variable speed drives: Modulates the speed of the blower or pump motors, achieving significant energy savings.

• Fuel storage

• Heat exchanger: Allows water heating at two different temperatures for space heating (hydronic) and domestic hot water.

• Exhaust chimney and combustion air intake

• Heater: When the outside temperature is very low, the boiler enclosure may require space heating to protect the components from freezing.

• Emergency shutdown: Manual stop in case of emergency.

The most common temporary boiler configurations are as follows:

Advantages and disadvantages of temporary boilers

Temporary boilers have advantages and disadvantages compared to permanent units. In general, they are intended for emergency situations and periods when there is an unexpected increase in demand for heating.

Final Observations

Temporary boilers are effective when buildings experience a boiler failure, when heating systems are being modernized, or when they face unexpected heating demand that exceeds installed capacity. However, they are not a long-term solution due to increased operating costs, noise and public exposure.