Permissible clearances, Limit of toxic vapors and gases – I.C.E. BMA-136 HBR User Manual
Page 11
10
TABLE II
PERMISSIBLE CLEARNCES WITH
SPECIFIED FORMS OF PROTECTION
(Clearance in Inches)
WHERE THE REQUIRED CLEARANCE WITH NO PROTECTION IS:
36 INCHES
18 INCHES
12 INCHES
6 INCHES
TYPE OF PROTECTION
SEE NOTE
ABOVE
SIDES
REAR
ABOVE
SIDES
REAR
ABOVE
SIDES
REAR
ABOVE
SIDES
REAR
¼” asbestos millboard spaced out 1”*
30
18
15
9
9
6
3
2
28 gauge sheet metal on ¼” asbestos
millboard
24
18
12
9
9
6
3
2
28 gauge sheet metal space out 1”*
18
12
9
6
6
4
2
2
28 gauge sheet metal on 1/8” asbestos
millboard spaced out 1”*
18
12
9
6
6
4
2
2
1-½” asbestos cement covering on heating
appliance
18
12
9
6
6
4
2
1
¼” asbestos millboard on 1” rockwool batts
reinforced with wire mesh or equivalent
18
12
6
6
4
4
2
2
22 gauge sheet metal on 1” rockwool batts
reinforced with wire mesh or equivalent
18
12
4
3
2
2
2
2
¼” asbestos cement board or ¼” asbestos
millboard
36
36
36
18
12
12
4
4
¼” cellular asbestos
36
36
36
18
12
12
3
3
*Spacer shall be of non combustible material
LIMIT OF TOXIC VAPORS AND GASES
DURING NORMAL OPERATION OF THE HEATER, THE CONTENT OF TOXIC VAPORS AND
GASES IN THE TEMPERED AIR AT THE POINT OF DISCHARGE INTO THE BUILDING MUST BE
SUCH THAT NO IRRITATING EFFECTS ARE EVIDENT. THE INSTALLATION SHALL NOT BE
CONSIDERED ACCEPTABLE IF THE DISCHARGE OF TOXIC PRODUCTS IS KNOWN TO EXCEED
THE LIMITS SET OUT IN THE FOLLOWING TABLE.
SUBSTANCE PERCENT PPM
SUBSTANCE PERCENT PPM
Acetaldehyde .001 10
Formaldehyde .000025 0.25
Carbon Dioxide .250 2500
Nitrogen Dioxide .0001 1
Carbon Monoxide .001 10
Sulfur Dioxide .00005 0.5
NOTE: At 100
°F the CO
2
concentration will be in the order of 2500 P.P.M.