MACH
®
Gas Fired Boiler
12
3.5
I
NLET
A
IR AND
E
XHAUST
V
ENTING
3.5.1 Applicable Codes & Standards
CODES
United States:
NFPA 54/ANSI Z223.1
National Fuel Gas Code
NFPA/ANSI 211
Chimneys, Fireplaces, Vents and Solid Fuel Burning Appliances
Canada
CAN/CSA B149.1
Installation Codes for Gas Burning Equipment
STANDARDS
UL 1738
Venting Systems for Gas-Burning Appliances, Categories II, III, and IV
ULC S636-95
Standard for Type BH Venting Systems
Sheet Metal and
Thermoplastic Duct Construction Manual
Air Conditioning Contractors
National Association (SMACNA)
These codes and standards contain information for the venting of gas fired appliances, including, but not limited to
vent sizing, location, clearance to combustibles, and safe installation practices. The installation must comply with
both the above Federal Codes and with state, provincial and local codes.
Design and installation of venting systems should be done only by qualified and
knowledgeable venting systems personnel and in accordance with vent system manufacturer’s
installation instructions. Installing a boiler or vent system using improper installation methods or
materials can result in serious injury or death due to fire or asphyxiation.
Before connecting a boiler to a venting system, it must be determined whether
the boiler is to be installed in a conventional or Direct Vent configuration. In the US, provisions for
combustion and ventilation air must be in accordance with NFPA 54/ANSI Z223.1,
National Fuel Gas
Code
, latest edition, or applicable provisions of the local building codes. In Canada, combustion and
ventilation air openings shall comply with CAN/CSA B-149.1
Natural Gas and Propane Installation Code
.
For correct installation of vent system, read all of these instructions and refer to
vent manufacturer’s instructions.
Failure to use a proper vent system (types and materials), as described in this manual will void the boiler
warranty and may result in rapid deterioration of the venting system, creating a health or life safety
hazard.
Faulty vent installation can allow toxic fumes to be released into living areas. This may cause property
damage, serious bodily injury or death.
3.5.1.1
Gas Vent Categories
Several codes and standards have categorized appliances in accordance with the flue gas temperature and pressure
produced by the appliance. Categories are defined as follows:
•
Category II
An appliance that operates with a non-positive vent static pressure and with a vent temperature
that may cause excessive condensate production in the vent.