Key Project Terms: Boiler (Building Systems Installation & Modifications)

The following is a list of useful terms to use when researching additional Boiler information on each of the topics discussed:

Boiler Work

Work may include: new installation, additions, alterations, modifications or repairs to the boiler installations, boiler appliances, oil tank(s) and components.

Boiler Types

High Pressure Boiler

A boiler that carries a pressure of more than fifteen pounds of steam per square inch (psig) and is rated in excess of ten horsepower, or that produces hot water over a pressure of one hundred sixty pounds per square inch or at a temperature over 250°F (121°C).

Low Pressure Boiler

  • Hot Water Heat.  A boiler which circulates hot water, not steam, for heating purposes in a loop which operates at pressures not exceeding 160 pounds per square inch (psig) and at temperatures not exceeding 250°F (121°C).
  • Hot Water Supply.  A water filled boiler which furnishes hot water to be used externally to itself, that operates at pressures not exceeding 160 psig and at temperatures not exceeding.
  • Steam Heat.  A steam generating boiler that operates at a pressure not exceeding 15 psig.


A device for the final conveyance of the gas, or a mixture of gas and air, to the combustion zone.

Certificate of Compliance

Per MC 107.2.4, a certificate of compliance is issued upon completion of the special inspection, and sign-off for the following service equipment:

  • Air conditioning and ventilation systems,
  • Fuel-burning and fuel-oil storage equipment, including generators,
  • Refrigeration systems
  • Heating systems, and
  • Boilers


A primarily vertical structure containing one or more flues, for the purpose of carrying gaseous products of combustion and air from a fuel-burning appliance to the outdoor atmosphere.

  • Factory-built chimney. A listed and labeled chimney composed of factory-made components, assembled in the field in accordance with manufacturer’s instructions and the conditions of the listing.
  • Masonry chimney. A field-constructed chimney composed of solid masonry units, bricks, stones or concrete.
  • Metal chimney. A field-constructed chimney composed of metal.


The minimum distance through air measured between the heat-producing surface of the mechanical appliance, device or equipment and the surface of the combustible material or assembly.


Refers to quality assurance testing process that verifies, and documents that the selected building systems have been designed, installed, and function according to the owner’s project requirements and construction documents, and to minimum code requirements. Mandatory when the permitted equipment exceeds a total heating capacity of 600 kBTU/h.

Confined Space

A space having a volume less than 50 cubic feet per 1,000 British thermal units per hour (Btu/h) (4.8 m3/kW) of the aggregate input rating of all appliances installed in that space.

Direct Venting

Appliances that are constructed and installed so that all air for combustion is derived directly from the outside atmosphere and all flue gases are discharged directly to the outside atmosphere.


Air being removed from any space, appliance or piece of equipment and conveyed directly to the atmosphere by means of openings or ducts.


A passageway within a chimney or vent through which gaseous combustion products pass.


A completely self-contained heating unit that is designed to supply heated air to spaces remote from or adjacent to the appliance location.

Key Points & Project Terms Categories

  1. Alterations

  2. Building Systems Installation & Modifications

  3. Construction Equipment

  4. Demolition


  5. New Buildings


  6. Renovations

Helpful Links