Lennox International Inc. GSB8-S 사용자 설명서

6

Air openings to combustion area must not 

be obstructed. Following instructions below, 

adequate combustion air can be maintained.

Provide combustion air and ventilation air in accordance 

with the section “Air for Combustion and Ventilation,” of the 

National Fuel Gas Code, ANSI Z223.1/NFPA 54, or Sections 

8.2, 8.3 or 8.4 of Natural Gas and Propane Installation 

Code, CAN/CSA B149.1, or applicable provisions of local 

building codes.
Provide make-up air where exhaust fans, clothes dryers, 

and kitchen ventilation equipment interfere with proper 

operation.
National Fuel Gas Code recognizes several methods 

of obtaining adequate ventilation and combustion air.  

Requirements of the authority having jurisdiction may 

override these methods.

Engineered Installations.  Must be approved by 

• 

authority having jurisdiction.

Mechanical Air Supply.  Provide minimum of 0.35 

• 

cfm per Mbh for all appliances located within space.  

Additional requirements where exhaust fans installed.  

Interlock each appliance to mechanical air supply 

system to prevent main burner operation when 

mechanical air supply system not operating.

All Indoor Air.  Calculate minimum volume for all 

• 

appliances in space.  Use a different method if 

minimum volume not available.

Standard Method.  Cannot be used if known air 

A. 

infi ltration rate is 0.40 air changes per hour.  See 

Table 1 for space with natural gas boiler only.  Use 

equation for multiple appliances and/or propane.

Volume ≥ 50 ft

3

 x Total Input [Mbh]

Known Air Infi ltration Rate.  See Table 1 for 

B. 

space with boiler only.  Use equation for multiple 

appliances.  Do not use an air infi ltration rate 

(ACH) greater than 0.60.

Volume ≥

 

21 ft

3

⁄ACH x Total Input [Mbh] 

    

 
Refer to National Fuel Gas Code for opening 

C. 

requirements between connected indoor spaces.

All Outdoor Air.  Provide permanent opening(s) 

• 

communicating directly or by ducts with outdoors.

Two Permanent Opening Method.  Provide opening 

A. 

commencing within 12 inches of top and second 

opening commencing within 12 inches of bottom of 

enclosure.

Direct communication with outdoors or 

 

…

communicating through vertical ducts. Provide 

minimum free area of 1 in² per 4 Mbh of total 

input rating of all appliances in enclosure.

Communicating through horizontal ducts.  

 

…

Provide minimum free area of 1 in² per 2 

Mbh of total input rating of all appliances in 

enclosure.

One Permanent Opening Method.  Provide opening 

B. 

commencing within 12 inches of top of enclosure.  

Provide minimum clearance of 1 inch on sides/back 

and 6 inches on front of boiler (does not supersede 

clearance to combustible materials).
Refer to National Fuel Gas Code for additional 

C. 

requirements for louvers, grilles, screens and air 

ducts.

Combination Indoor and Outdoor Air.  Refer to National 

• 

Fuel Gas Code for application information.

Table 3 - Minimum Room Volume, Indoor Air Only*

Input Mbh

Standard 

Method

Known Air Infi ltration Rate Method (Air Changes Per Hour)

0.1

0.2

0.3

0.4

0.5

0.6

75

3750

15750

7875

5250

3938

3150

2625

112.5

5625

23625

11813

7875

5906

4725

3938

150

7500

31500

15750

10500

7875

6300

5250

187

9350

39270

19635

13090

9818

7854

6545

255

11250

47250

23625

15750

11813

9450

7875

262.5

13125

55125

27563

18375

13781

11025

9188

299

14950

62790

31395

20930

15698

12558

10465

* Table values based on boiler only. Add volume for any additional appliances.