Arreglo Iri
Section 2
Sheet R-2
IRI Requirements For Gas Burner Systems
General Remarks:
The schematic and notes on the following pages condense the gas
burner system requirements ofIndustrial Risk Insurers (IRI) into an
easy-to-use format. They should provide most of the engineering
information required to lay out burner air and gas trains. In general,
IRI follows the requirementsof National Fire Protection Association
(NFPA) 86, but adds a vent valve.
In addition to the requirements shown on the schematic, IRI also
requires that the combustion control system have thefollowing
features:
1) Forced low fire lightoff of burners that cannot be safely ignited at
all firing rates.
2) Prior to energizing spark or lighting pilot, a timed prepurge of at
least fourstandard cubic feet of air per cubic foot of furnace or
oven volume. Purging of radiant tubes, however, is not required.
3) Except for burners with inputs not exceeding 150,000 Btu/hr
(44kW) and radianttube burners, direct spark igniters must be
shut off after main burner trial-for-ignition.
4) Trial-for-ignition of pilots or main burners must not exceed 15
seconds.
5) Automatic relight(recycling) after unintentional flame failure is
prohibited.
6) Safety control circuits must be single phase, one side grounded,
with all breaking contacts in the “hot”, ungrounded fuse (or circuitbreaker) protected line. Maximum line voltage is 120V.
Piping and electrical schematics of the proposed system must be
submitted to the local IRI office in whose jurisdiction the system will be
located.Schematics must be approved and stamped before
construction begins.
105
Piping Schematic
3
3
3
3
4
5
2
15
7
10
7
9
1
6
Gas Flow
Controls
Gas
12
813
14
Air Flow
Controls
106
11
Item
Description
1
Individual manual shutoff valve to each piece of equipment. 1/4 turn valves
recommended.
2
Pressure regulator...
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