248 CMR 5.12
Modifications to Chapter 12, Venting of Appliances
(1) Delete sub-section 12.4.4.2 and replace with the following:
12.4.4.2 Venting via a Damper or with a Power Means of Exhaust. Where gas appliances or
equipment are vented through a ventilating or exhaust system equipped with a damper or with
a power means of exhaust, provisions shall be made to allow the flow of gas to the main burners
only when the damper is open to a position to properly vent the appliance or equipment when
the power means of exhaust is in operation. All gas lines serving such appliances or equipment
shall be equipped with a solenoid valve which meets the following criteria:
(a) The solenoid valve may not be bypassed.
(b) The solenoid valve must be equipped with or connected to a manual reset device
controlled by one of the following options:
1. at least one audible hard wired carbon monoxide detector listed for the environment
in which the appliance or equipment is being installed. This carbon monoxide detector
must be interlocked with the solenoid valve such that it will close the solenoid valve if
an unsafe level of carbon monoxide is reached in the room or the detector becomes
defective.
2. a draft proving switch which allows the solenoid valve to be open only when:
a. the equipped damper is 100% open; or
b. the power means of exhaust is fully operational.
(c) Notwithstanding the provisions of subsection 1.3 (Retroactivity), installers of
replacement appliances or equipment used in connection with ventilating hoods or exhaust
systems must ensure that the gas line(s) serving the replaced appliances or equipment meet
the requirements of subsection 12.4.4.2.
Plastic Piping. The only plastic piping which may be used for venting appliances shall be CPVC,
polypropylene, and other pipes which have been Product-accepted for that purpose by the Board.
(3) Replace sub-section 12.6.4.2, Exception with the following:
Exception: Chimneys which are tile lined or existing chimneys which do not meet the
requirements of sub-section 12.6.4.2 may be utilized with the replacement or installation of a gas
appliance, including a gas appliance replacing an oil appliance, when the following requirements
are met:
(a) The existing appliance must have operated with a non-positive vent static pressure that
did not create condensation in the chimney.
(b) Existing chimneys may not be utilized when replacing an atmospheric appliance with
a fan assisted appliance; and
(c) An existing chimney may only be utilized with one or multiple gas appliances if the
interior area of the chimney is no greater than seven times the area of the smallest flue to be
connected to that chimney.
(4) Add a new sub-section 12.7.6.1 as follows:
12.7.6.1 Marking of Schedule 40 PVC and Other Non-metallic Piping. Schedule 40 PVC and
other non-metallic piping used for ventilation, make-up, or combustion air intake shall be labeled
as follows:
(a) Throughout the entire developed length:
1. Labels must be placed every ten feet for exposed/visible piping; or
2. Labels must be placed every three feet for concealed piping.
(b) At all changes of direction;
(c) On each side of a penetration through a partition, wall or ceiling; and
(d) The labels shall be black lettering that:
1. indicates that the piping is used for ventilation, make-up, or combustion air intake,
and
2. the letters shall be sized equal to a minimum of the pipe diameter. However, for
piping with a diameter exceeding two inches, said lettering does not need to be larger
than two inches.
(5) Delete the last sentence of sub-section 12.9.4.
(6) Add a new subsection 12.9.7 as follows:
12.9.7 Signage. Whenever any through-the-wall vent is installed less than seven feet above the
finished grade, a metal or plastic identification plate shall be permanently mounted to the exterior
of the building at a minimum height of eight feet above grade directly in line with the exhaust
vent terminal. The sign shall read, in print size no less than 0.5 inches in size, "GAS VENT
DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".
(7) Add a new sub-section 12.9.8 as follows:
12.9.8 Vent Termination or Intake. A side wall horizontal exhaust vent termination or intake
for gas fueled equipment installed in every dwelling, building or structure shall be located no less
than three feet from a gas meter. When manufacturer's installation instructions reference snow
lines or levels in establishing a minimum height for the installation of an exhaust vent
termination or intake, snow lines or levels shall be determined as follows:
(a) from the manufacturer installation requirements when those requirements are specific
as to the source and method for the calculation of snow lines/levels;
(b) when the installation instructions are not specific as to how snow lines/levels are
calculated, the city or town may, by ordinance, designate how snow lines/levels are
calculated in that location; or
(c) In the absence of specific manufacturer instructions or ordinances, snow lines/levels
shall be calculated from the average monthly maximum depth of snow accumulation as
indicated by the National Weather Service's ten year statistics for the installation
location/geographical area.
(8) Delete section 12.10.
12.11.6 Joints. Joints between sections of connector piping and connections to flue collars or
draft hood outlets shall be fastened in accordance with one of the following methods:
(a) The fastening of single wall metal piping shall utilize no less than three corrosion
resistant fastening devices to secure each joint;
(b) Vent connectors of listed vent material assembled and connected to flue collars or draft
hood outlets in accordance with the manufacturers' instructions; or
(c) Other approved means.