What do the fire door rating numbers mean on a fire door tag? Understanding the fire door rating is essential for confirming fire door compliance and ensuring a door performs as intended during a fire. The fire resistance rating shown on a fire door tag is made up of four performance measures that define how a fire door responds under fire conditions.
Understanding Fire Door Rating Numbers
The fire resistance code displayed on a fire door tag is made up of four measures:
• Stability
• Integrity
• Insulation
• Smoke rating
A typical fire door rating may look like:
– / 60 / 30 / SM
The numbers represent minutes of performance for each measure, while SM indicates whether the door is a smoke rated fire door.
What Each Fire Door Rating Means
Stability
The stability rating measures how long a structural element can withstand fire exposure while maintaining its load-bearing function. Because a fire rated door is not load bearing, its stability value is always zero and is shown as a dash ( – ) on the fire door tag.
Integrity
The integrity rating refers to the fire door’s ability to prevent the passage of flames, hot gases, and smoke during a fire. This part of the fire resistance rating indicates how long the fire door remains intact and continues to block fire spread.
Insulation
The insulation rating measures how well a fire door limits temperature rise on the non-fire side of the door for a specified period. This element of the fire door rating helps protect occupants escaping and prevents heat transfer that could damage adjacent spaces.
Smoke Rating (SM)
A smoke rated fire door is designed to restrict the spread of smoke between compartments. Smoke performance is achieved using smoke seals fitted to the vertical edges and the head of the door. Smoke is not measured in minutes; instead, the fire door tag will indicate SM, meaning the door either is smoke rated or it is not.
Fire Door Tags and Compliance
Once installed, a compliant fire door set will have a fire door tag fixed to the hinge side of the door leaf and to the door frame. This tag confirms:
• The fire resistance rating
• The insulation rating
• Whether the door is smoke rated
Correct tagging is a key part of fire door compliance and provides confidence that the door has been tested, certified, and installed correctly.
Final Thoughts
Being able to read and understand a fire door tag is essential for architects, specifiers, contractors, and building owners. Clear knowledge of fire door rating numbers ensures that fire doors are specified correctly, installed properly, and perform as required in an emergency. Understanding these details helps maintain fire door compliance and supports life safety across the building.
