Installation Sheet

Polypropylene (PP) Common Venting Installation Instructions 21

Louvers and Grills

When sizing the permanent opening consideraon

must be taken for the design of the louvers or grills to

maintain the required free area required for all gas

ulizing equipment in the space. If the free area of the

louver or grill design is not available, assume wood

louvers will have 25% free area and metal louvers or

grills will have 75% free area. Under no circumstance

should the louver, grill or screen have openings

smaller than 1/4”.

Example:

Wood: 10 in x 12 in x 0.25 = 30 in

Metal: 10 in x 12 in x 0.75 = 90 in

Locaon

To maintain proper circulaon of combuson air two

permanent openings (one upper, one lower) must be

posioned in conned spaces. The upper shall be

within 12” of the top of the conned space and the

lower opening shall be within 12” of the boom of the

conned space. Openings must be posioned as to

never be obstructed.

Using Outdoor Air For Combuson

Outdoor air can be provided to a conned space

through two permanent openings, one commencing

within 12 in. (300mm) of the top and one commencing

within 12” (300mm) of the boom, of the conned

space. The openings shall communicate to the outside

by one of two ways.

Vent terminaon per ANSI Z223.1/NFPA 54. For

clearances not specied in ANSI Z223.1/NFPA 54,

clearances are in accordance with local installaon

codes and the requirements of the gas supplier.

(Be sure to also maintain 12” above grade or

ancipated snow level)

Combuson Air Requirements

Exhaust