scope:

This standard applies to newly produced gas-fired low-pressure steam and hot water boilers with gas inlet pressure ratings not exceeding 1/2 psi (3.5 kPa) and having input ratings of less than 12,500,000 Btu/hr (3 663 389 W) (see Part IV, Definitions), hereinafter referred to as boilers*, constructed entirely of new unused parts and materials, for operation at or below the following pressures and temperatures:

Steam heating boilers 15 psi (103.42 kPa) steam pressure

Hot water heating boilers 160 psi (1.10 MPa) water pressure 250°F (121°C) water temperature Hot water supply boilers 160 psi (1.10 MPa) water pressure 250°F (121°C) water temperature

a. For use with natural gas;

b. For use with manufactured gas;

c. For use with mixed gas;

d. For use with liquefied petroleum gases; and

e. For use with LP gas-air mixtures.

The construction of boilers for use with the above-mentioned gases is covered under Part I.

The performance of boilers for use with the above-mentioned gases is covered under Part II.

This standard applies to indoor type boilers, of other than the direct vent which are categorized according to vent pressure and temperature as either Category I, Category II, Category III or Category IV (see Part IV, Definitions), and to outdoor type boilers.

This standard also applies to direct vent boilers (see Part IV, Definitions). A direct vent boiler anticipated by this standard is essentially a balanced flue appliance with the air intake and vent outlet in proximity. Other designs shall be subjected to such additional tests as believed necessary at the discretion of the testing agency.

This Standard covers the method of test to determine combustion efficiency for indoor boilers with input rates of 300,000 Btu/hr (87 921 W) or greater and the thermal efficiency for both indoor and outdoor boilers. [See Exhibit E, Items Unique to Canada, for minimum efficiencies of indoor boilers with input rates under 300,000 (87 921 W) for sale in Canada].

If a value for measurement as given in this standard is followed by an equivalent value in other units, the first stated value is to be regarded as the specification.

All references to pressure throughout this standard are to be considered gauge pressure, unless otherwise specified.

Exhibit E, Items Unique to Canada, contains provisions unique to, and required by, Canada.