The Dryerbox has been classified by Underwriters Laboratories, Inc. for models 350, 425, 480, 3D, and 4D for use in Through-Penetration Underwriters Laboratories Through Penetration Firestop System Firestop System Number W-L-7129.
Underwriters Laboratories Certifications Directory reference numbers: XHGK.R21933 (US), XHGK7.R21933 (CANADA) and XHEZ.W-L-7129 (FIRESTOP SYSTEM). Cabinets For Use in Penetration Firestop Systems See UL Fire Resistance Directory <25XC>
These key components are noted on the instruction sheet that comes with every Dryerbox. The following are highlights to comply with the UL Classification for through-penetration firestop systems. To achieve a fire resistance rating (one-hour F & T) 2X6 framing is required. The Dryerbox unit must be installed in accordance with the UL Cabinet System listing.
Drywall requirements: An extra layer of type-X drywall must be installed in the ID of the stud cavity in which the Dryerbox is located. Drywall must be attached to nailers (minimum 1" X 2") located on the inside of the cavity wall studs. Secure nailers to wall framing at max 18 in. OC. The screws used to attach the inner layer of drywall shall be spaced a maximum of 18 inches apart.
|350, 425, 3D and 4D||Wood||See Note 1|
|350, 425, 3D and 4D||Steel||See Note 2|
|480||Steel and Wood||See Note 3|
Note 1: The entire depth of stud cavity with DryerboxÂ® must be filled with R19 fiberglass batt insulation. Additional insulation shall be added within the cavity as necessary to completely fill all voids around the periphery of the Dryerbox and around the dryer vent pipe.
Note 2: The entire wall cavity containing the cabinet shall be tightly packed to full stud depth and cavity height with mineral wool batt insulation having a min density of 4 pcf. In addition, the wall stud cavities immediately adjacent to the cavity with the cabinet shall be insulated with min R13 glass fiber batt insulation (or min 4 pcf mineral wool batt material) for the full depth and height of the stud cavity.
Current building code only requires a 1/2 hour rating for Dryerbox® installation when used in conjunction with a sprinkler system. You may find the full, relevant code excerpt below. To achieve a half hour rating, you only need to build out using Firestop System Configuration A Wall Assembly Components which are even simpler. (1 Hour Rating Requires Configuration B as outlined above)
Corridors shall be fire-resistance rated in accordance with Table 1018.1. The corridor walls required to be fire-resistance rated shall comply with Section 708 for fire partitions.
|Occupancy||Occupant Load Served by Corridor||Without sprinkler system||With sprinkler systemc|
|H-1, H-2, H-3||All||Not Permitted||1|
|H-4, H-5||Greater than 30||Not Permitted||1|
|A, B, E, F, M, S, U||Greater than 30||1||0|
|R||Greater than 10||Not Permitted||0.5|
|I-2a, I-4||All||Not Permitted||0|
|I-1, I-3||All||Not Permitted||1b|
You may find ancillary white papers and engineering letters on the Architects & Engineers pages in addition to the engineering letters below that detail back to back installation options.