Mascot LX Boilers and Water Heaters
Page 15
3.3.3 Vertical Vent Terminal
When the unit is vented through the roof, the vent must
extend at least 3 feet (0.9m) above the point at which it
penetrates the roof. It must extend at least 2 feet (0.6m)
higher than any portion of a building within a horizontal
distance of 10 feet (3.0m), and high enough above the
roof line to prevent blockage from snow. When the
combustion air is taken from the roof, the combustion
air must terminate at least 12" (30cm) below the vent
terminal (
see Figure 11
).
3.3.4 Vertical Combustion Air Terminal
When combustion air is taken from the roof, a field-
supplied rain cap or an elbow arrangement must be
used to prevent entry of rain water (
see Figure 11
). The
opening on the end of the terminal must be at least 12"
(30cm) above the point at which it penetrates the roof,
and high enough above the roof line to prevent blockage
from snow. When the vent terminates on the roof, the
combustion air must terminate at least 12" (30cm) below
the vent terminal.
3.3.5 Installations in the Commonwealth of
Massachusetts
In Massachusetts the following items are required if the
side-wall exhaust vent termination is less than seven
(7) feet above finished grade in the area of the venting,
including but not limited to decks and porches. From
Massachusetts Rules and regulations 248 CMR 5.08
1. Installation of Carbon Monoxide Detectors
At the time of installation of the side wall vented
gas fueled appliance, the installing plumber or gasfitter
shall observe that a hard-wired carbon monoxide
detector with an alarm battery back-up is installed on the
floor level where the gas appliance is to be installed. In
addition, the installing plumber or gasfitter shall observe
that a battery operated or hard-wired carbon monoxide
detector with an alarm is installed on each additional
level of the dwelling, building or structure served by
the side-wall horizontally vented gas fueled equipment.
It shall be the responsibility of the property owner to
secure the services of qualified licensed professionals for
installation of hard-wired carbon monoxide detectors.
a. In the event that the side-wall horizontally
vented gas fueled equipment is installed in a crawl
space or an attic, the hard-wired carbon monoxide with
alarm and battery back-up may be installed on the next
adjacent floor level.
b. In the event that the requirements of the
subdivision cannot be met at the time of completion of
installation, the owner shall have a period of thirty (30)
days to comply with the above requirements, provided,
however, that during said thirty (30) day period, a
battery operated carbon monoxide detector with an
alarm be installed.
2. Approved Carbon Monoxide Detectors
Each carbon monoxide detector shall comply
with NFPA 720 and be ANSI/UL 2034 listed and IAS
certified.
3. Signage. A metal or plastic identification plate
shall be permanently mounted to the exterior of the
building at a minimum height of eight (8) feet above
grade directly in line with the exhaust vent terminal
for horizontally vented gas fueled heating appliance
or equipment. The sign shall read, in print no less than
one-half (1/2) inch in size: "GAS VENT DIRECTLY
BELOW, KEEP CLEAR OF ALL OBSTRUCTIONS".
4. Inspection
The state or local gas inspector of the side-wall
horizontally vented gas fueled appliance shall not
approve the installation unless, upon inspection, the
inspector observes carbon monoxide detectors and
signage installed in accordance with the provisions of
248 CMR 5.08(2)(a) 1-4.
