Boiler Manual
Part Number 550-110-593/1099 11
Special considerations

Tight construction

ANSI Z223.1 defines unusually tight construction
where:
a. Walls and ceilings exposed to the outside
atmosphere have a continuous water vapor retarder
with a rating of 1 perm or less with openings
gasketed, and . . .
b. Weather-stripping has been added on openable
windows and doors, and . . .
c. Caulking or sealants are applied to areas such as
joints around windows and door frames, between
sole plates and floors, between wall-ceiling joints,
between wall panels, at penetrations for plumbing,
electrical, and gas lines, and in other openings.
For buildings with such construction, provide air
openings into the building from outside, sized per the
appropriate case in Figure 3 if appliances are to use
inside air for combustion and ventilation.
Air
opening
Air
opening
0 to 12"
0 to 12"
Other
appliances
CGa
boiler