Preface
This is the twenty-ninth edition of ANSI Z21.11.2, Gas-fired room heaters, volume II, unvented room heaters. It supersedes the previous editions published in 2016, 2013, 2011, 2007, 2000, 1996, 1992, 1989, 1983, 1978, 1974, 1971, 1967, and 1962.
Scope
1.1
This Standard applies to newly produced gas-fired unvented room heaters for connection to the house fuel supply system (see Clause 3), hereinafter referred to as room heaters or appliances, constructed entirely of new, unused parts and materials, having input ratings up to and including 40,000 Btu/hr (11,723 W) except:
a) unvented room heaters suitable for installation in bedrooms have input ratings of 10,000 Btu/hr (2,931 W) or less; and
b) unvented room heaters suitable for installation in bathrooms have input ratings of 6000 Btu/hr (1,758 W) or less.
1.2
This Standard covers unvented room heaters that comply with either of the following types:
a) shipped from the factory equipped specifically for use with one gas only. Field conversion of gas types by any means including the use of a kit are not permitted;
or b) a universal unvented room heater shipped from the factory equipped with a switching means for selecting the type of gas to which it is being connected.
1.3
Unvented room heaters are:
a) for use with natural gas;
b) for use with manufactured gas;
c) for use with mixed gas;
d) for use with propane gas;
e) for use with LP gas-air mixtures; and
f) for manufactured (mobile) home aftermarket installation for use with natural gas only or for use with propane gas only.
1.4
Universal unvented room heaters are:
a) for use with propane and for use with natural gas when provision is made for a switching means from one gas to the other; and
b) for manufactured (mobile) home or mobile home aftermarket installation for use with propane and for use with natural gas when provision is made for a switching means from one gas to the other (see Clause 4.1.5).
1.5
Unvented room heaters for installation in bathrooms are to be wall-mounted. Unvented room heaters for installation in bedrooms are to be wall-mounted or for installation in solid-fuel burning fireplaces.
An unvented gas log (see Clause 3), provided with means for mounting the burner base assembly to the floor of the solid-fuel burning fireplace, shall be considered as complying with the wall-mounted requirement for installation in bedrooms or bathrooms.
1.6
The construction of unvented room heaters for use with the above-mentioned gases is covered under Clause 4.
1.7
The performance of unvented room heaters for use with the above-mentioned gases is covered under Clause 5.
1.8
This Standard covers appliances shipped from the factory equipped specifically for one gas only. Field conversion of gas types is not permitted.
1.9
Special construction provisions applicable to room heaters for manufactured (mobile) home aftermarket installation are outlined under Clauses 1.3 f), 4.20.4, and 4.21.3 j).
1.10
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.
1.11
All references to psi throughout this Standard are to be considered gauge pressure unless otherwise specified.
1.12
Clause 2 contains a list of standards referenced in this Standard, and sources from which these reference standards may be obtained.
1.13
In this Standard, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the Standard.
Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements.
Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.
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