Office Policy: Fire Protection Of Transformer Vaults

Office Policy: Fire Protection Of Transformer Vaults

Office Policy: Fire Protection of Transformer Vaults

From: Fire Marshal M. M. Stone
Date: October 2, 1997

image of people workingRecent developments in various construction projects haveraised concerns of fire protection in main electrical servicetransformer vaults. The following will be considered as OfficePolicy for all projects permitted after this date.


This office recommends the installation ofservice main electrical transformers be located outside thefootprint of the building they serve.

When service main electrictransformer vaults are located within the footprint of thebuilding, the following design criteria shall be used for vaultconstruction.

Total enclosure with 4-hour fire resistiveconstruction

Class "A" opening protective

All penetrations sealed with tested assemblefor that use

Fire detection equipment tied to thebuildings fire alarm system

image of welder

Transformers shall be the only equipmentpermitted within the vault area

Signage shall be provided on the exterior ofwalls indicated "High Voltage"

Signage shall be provided on the entry doorsindicating:

"Authorized personnel only"

"Emergency phone numbers"

Access shall be regulated by the utilitycompany

Sprinkler heads shall be deleted from thevault area as with the above listed requirements the vault areacan be classified as outside of the building.