Steel Door Inc.

Trending Questions on Fire Ratings and Smoke Doors

It's been SDI's long-standing goal to continuously develop free and easy to understand information on steel doors and frames. More than 20,000 people a month rely on SDI's standards, videos, FAQ, and online courses for the information they need.

When the website doesn't have the information you're seeking, we welcome you to contact SDI with questions on standards or general steel door and frame inquiries. (Please contact the manufacturer with product-specific questions.)

When the same question keeps coming up, we like to answer it in the FAQ or newsletter so it helps others who may be wondering the same thing. The two questions below have been asked by numerous architects lately.

Three Hour Fire Walls

Table 1 in SDI-118 (below) shows the required fire ratings of walls and door assemblies for a variety of openings. We are often asked what rating a door assembly should have when paired with a 3 hour wall.

SDI-118 - Basic Fire Door, Fire Door Frame, Transom/Sidelight Frame, and Window Frame Requirements

Per the International Building Code (IBC) 2015, a three hour wall should have a three hour door assembly.

Table 716.5 of the IBC-2015

No Smoking

A number of architects have asked questions about 20 minute smoke control doors, often referring to them as 'smoke doors' and 'fire doors' interchangeably. Some asked if 20 minute smoke doors are inherently fire rated for 20 minutes.

They are not, however most 20-minute doors would be required to have the S label because they are often located in corridors and smoke barriers. The S in the fire label below shows that this fire door is also rated for use as a smoke door assembly, and therefore has to be installed and maintained per NFPA 105 — Standard for Smoke Door Assemblies and Other Opening Protectives.