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The 24 Inch Rule for Electrical Outlets in 2 hour Fire Rated Walls

Posted by BIP on 28th Nov 2017

  

It's common knowledge that penetrations (pipes, wires, ducts) through fire-rated walls must be properly firestopped, however the fact that electrical outlets must also be treated is often overlooked.  In regards to fire-rated walls, electrical outlets and light switches must be treated with firestop materials.

The "24 Inch Rule" for Fire-Rated Walls

When installing outlets and light switches in fire-rated walls, there are a few fire-related regulations and electrical codes regarding the placement of these penetrations.  No two outlets/switches may be placed in the same cavity between wall studs.  This includes the outlets on the other side of the wall as well.  All boxes must also have more than 24 inches of horizontal spacing between outlets on either side of the fire rated wall.  This means that on 24" OC studs, outlets must be placed at least one stud cavity away (both sides of wall).  On 16" OC studs, outlets must be placed approximately two stud cavities away (both sides of wall).

If a 2 hour fire-rated wall fails the 24" inch rule regulation during a fire inspection there are two simple products that can be easily installed to the outlets to pass the fire code.  Metacaulk Cover Guards are installed on the inside of the outlet cover plate, and Metacaulk Box Guards are installed on the inside back wall of the outlet.  Both of these firestop products will provide a passing grade on outlets that are within 24 inches to an outlet on the backside of the wall.

Most common uses are hospitals, nursing homes, long-term care facilities, garage walls, etc.

Firestop Materials for Electrical Receptacles & Switches


Metacaulk Fire Rated Putty Pads:  These stick "play dough" like pads are installed to the back of an electrical outlet to provide proper fire stopping to the outlet penetration.  Unfortunately these pads are limited to new construction as the wall cavity must be open to install properly.



Metacaulk Box Guards: Cover-Guards are single component fire-rated gaskets for use in electrical outlet boxes on fire-rated walls. Cover-Guards are the quick and easy way to comply with the "24 Inch Rule". Cover-Guards install easily and fit right behind metal or plastic outlet cover plates. Cover-Guards come in both standard and decor style in both single and double gang outlet covers and double and single switch covers.

 

Metacaulk Cover Guards: Cover-Guards are single component fire-rated gaskets for use in electrical outlet boxes on fire-rated walls. Cover-Guards are the quick and easy way to comply with the "24 Inch Rule". Cover-Guards install easily and fit right behind metal or plastic outlet cover plates. Cover-Guards come in both standard and decor style in both single and double gang outlet covers and double and single switch covers.

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