ANSI Z21.13-2013/CSA 4.9-2013

Preface

This is the Fourth edition of ANSI Z21.13 - CSA 4.9, Gas-fired low pressure steam and hot water boilers. 

Scope

1.1

This Standard applies to newly produced gas-fired low-pressure steam and hot water boilers with gas inlet pressure ratings not exceeding ½ psi (3.5 kPa) and having input ratings of less than 12,500,000 Btu/hr (3 663 389 W) (see Clause 3), 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 Clause 4. 

The performance of boilers for use with the above-mentioned gases is covered under Clause 5. 

* See Clause 7 (7.2.1) for boilers covered in Canada which exceed the above limits in gas inlet pressure and/or input ratings. 

1.2
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 Clause 3), and to outdoor type boilers. 

1.3
This Standard also applies to direct vent boilers (see Clause 3). 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. 

1.4
See Clause 7 for the Canadian Method of test to determine combustion efficiency for indoor boilers and the thermal efficiency for both indoor and outdoor boilers. 

1.5
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. 

1.6
This Standard contains SI (Metric) corresponding to the yard/pound quantities, the purpose being to allow the standard to be used in SI (Metric) units. (Standard for use of the International System of Units (SI): The Modern Metric System, IEEE/ASTM SI 10 or ISO 80000-1:2009 Quantities and units - Part 1: General are used as a guide in making metric conversion from yard/pound quantities.) If a value for a measurement and a corresponding value in other units are stated, the first stated value is to be regarded as the requirement. The given corresponding value may be approximate. If a value for a measurement and corresponding value in other units are both specified as a quoted marking requirement, the first stated unit, or both shall be provided. 

1.7
All references to pressure throughout this standard are to be considered gauge pressure, unless otherwise specified. 

1.8
Clause 7 contains provisions unique to, and required by, Canada.