RBI SERIES 8800 Installation & Operation Manual page 5

SERIES 8800 & 8900 INSTALLATION AND OPERATING INSTRUCTIONS
Where communicating with the outdoors through
horizontal ducts, each opening shall have a minimum
free area of 1 in 2 /2000 Btu/hr, 1100 mm
input rating of all of the equipment in the enclosure.
When ducts are used, they must have the same cross-
sectional area as the free area of the opening to which
they connect.
Canadian installations must comply with CSA B149.1
when air supply is provided by natural air flow from the
outdoors for natural draft , partial fan-assisted, fan-
assisted, or power draft-assisted burners , there shall
be a permanent air supply opening(s) having a cross-
sectional area of not less than 1 in
per kW) up to and including 1 million Btuh,
(310 mm 2
2
plus 1 in per 14,000 Btuh (155 mm
of 1 million Btuh.
When calculating the free area necessary to meet
the make-up air requirements of the enclosure,
consideration must be given to the blockage effects
of louvers, grills and screens. Screens must have
a minimum mesh size of 1/4 in, 6.4 mm . If the free
area through a louver or grill is not known, ducts
should be sized per Table 2.
Figure 1 - Vertical Venting Using A Metal Chimney And Inside Air (8900/8800 Series)
2 FT .6 m
10 FT 3.4 m
2 /kW of the total
2 per 7,000 Btuh
2 per kW) in excess
3 FT 1 m
3 FT 1 m
5 FT 1.52 m
Table 2 - Make-up Air Louver Sizing
Required Cross Sectional Area
1/4 in 6.4 mm 75% Free Area
Input
(MBH) Wire Screen
in 2 cm 2
105
420 677
133
530 858
158
630 1019
184
735 1187
840 210 1355
238 1535
950
263
1050 1697
290
1160 1871
315
1260 2032
343
1370 2213
1470 368 2374
395 2548
1580
421
1685 2716
448
1790 2890
475
1900 3065
500
2000 3226
2400 600 3871
700 4516
2800
800
3200 5161
900
3600 5806
1000
4000 6452
25% Free Area
Metal Louvers Wooden Louvers
in 2 cm 2 in 2
140 420
903
177 530
1142
210 630
1355
245 735
1581
280 1806 840
317 2032 950
350 1050
2258
387 1160
2497
420 1260
2710
457 1370
2948
490 3161 1470
527 3400 1580 10,194
562 1685 10,871
3626
597 1790 11,548
3852
633 1900 12,258
4084
667 2000 12,903
4303
800 5161 2400 15,483
933 6019 2800 18,064
1067 3200 20,645
6884
1200 3600 23,226
7742
1333 4000 25,806
8600
RIOM-40
Page 5
cm 2
2710
3419
4064
4742
5419
6129
6774
7484
8129
8839
9484