Burnham L7248 manual Minimum Installation Clearances To Combustible Materials

Figure 2: Minimum Installation Clearances To Combustible Materials

NOTE 1: Listed clearances comply with American National Standard ANSI/NFPA 31, Installation of oil burning equipment.

NOTE 2: LE Series boilers can be installed in rooms with clearances from combustible material as listed above. Listed clearances can not be reduced for alcove or closet installations.

NOTE 3: For reduced clearances to combustible material, protection must be provided as described in the above ANSI/NFPA 31 standard.

3. PROVIDE COMBUSTION AND VENTILATION AIR. Local code provisions may apply and should be referenced.

WARNING

Adequate combustion and ventilation air must be provided to assure proper combustion.

A.Determine volume of space (boiler room). Rooms communicating directly with the space in which the appliances are installed, through openings not furnished with doors, are considered a part of the space.

Volume(ft3) = Length(ft) x Width(ft) x Height(ft)

B.Determine total input of all appliances in the space.

Add inputs of all appliances in the space and round the result to the nearest 1000 BTU per hour.

C.Determine type of space. Divide Volume by total input of all appliances in space. If the result is greater than or equal to 50 ft3/1000 BTU per hour, then it is considered an unconfined space. If the result is less than 50 ft3/1000 BTU per hour then the space is considered a confined space.

D.For boiler located in an unconfined space of a conventionally constructed building, the fresh air infiltration through cracks around windows and doors normally provides adequate air for combus- tion and ventilation.

E.For boiler located in a confined space or an uncon- fined space in a building of unusually tight con- struction, provide outdoor air with the use of two permanent openings which communicate directly or by duct with the outdoors or spaces (crawl or attic) freely communicating with the outdoors. Locate one opening within 12 inches of top of space. Locate remaining opening within 12 inches of bottom of space. Minimum dimension of air opening is 3 inches. Size each opening per following:

(1)Direct communication with outdoors. Minimum free area of 1 square inch per 4,000 BTU per hour input of all equipment in space.

(2)Vertical ducts. Minimum free area of 1 square inch per 4,000 BTU per hour input of all equipment in space. Duct cross-sectional area shall be same as opening free area.

(3)Horizontal ducts. Minimum free area of 1 square inch per 2,000 BTU per hour input of all equipment in space. Duct cross-sectional area shall be same as opening free area.

Alternate method for boiler located within confined space. Use indoor air if two perma- nent openings communicate directly with additional space(s) of sufficient volume such that combined volume of all spaces meet criteria for unconfined space. Size each opening for minimum free area of 1 square inch per 1,000 BTU per hour input of all equipment in spaces, but not less than 100 square inches.

F.Louvers and Grilles of Ventilation Ducts

(1)All outside openings should be screened and louvered. Screens used should not be smaller than 1/4 inch mesh. Louvers will prevent the entrance of rain and snow.

(2)Free area requirements need to consider the blocking effect of louvers, grilles, or screens protecting the openings. If the free area of the louver or grille is not known, assume wood louvers have 20-25 percent free area and metal louvers and grilles have 60-75 percent free area.