While we were discussing the lack of positive-latching on these doors, someone mentioned that 20-minute doors didn’t need positive-latching at one point in time. It should also be noted that a smoke barrier in an existing building is required to be constructed with a 1-hr fire resistance rating, but may be protected with 1 3/4" solid bonded wood core doors or the equivalent, ref. used in one-hour walls. Some architects do specify 20-minute fire rated doors in smoke barriers, and while this practice is not a violation of the LSC, it does present a burden on the healthcare facility because now they have to maintain it as a fire rated door, even though it is not required to be a fire rated door. Metal fire doors are an economical alternative to wood fire doors, when more than a 20 minute rating is required. With a combination of specialty materials and manufacturing processes, real wood door frames can be created that rate 45, 60 and even as high as 90 minutes. 21.3.7.1(2). I had just received a copy of the 1961 edition of NFPA 80 that I bought on eBay for $4.99, so I looked for the 1961 requirements for 20-minute doors. Encore Doors – 90-, 60-, 45- and 20-minute fire ratings available; 20-minute Wood Fire-Rated Doors. Fire Rated Door and Frame Labels / Ratings - archtoolbox.com Introducing 20-Minute Fire-Rated Glass Doors TruStile’s 20-minute fire-rated glass doors are built with the same premium construction as TruStile’s other stile and rail doors. Fire-Rated steel doors play a vital role in keeping people safe and minimizing property damage during a fire. with This exception to the rule only applies to 20 minute rated fire doors. Fire-Rated Doors and Frames. Introducing 20-Minute Fire-Rated Glass Doors TruStile’s 20-minute fire-rated glass doors are built with the same premium construction as TruStile’s other stile and rail doors. The 20 minute door is the now-current definition of a 1-3/4" solid core wood door. FIRE RATED DOOR AND FRAME . ... Glass with this designation has be tested to meet impact safety requirements required for areas such as doors, sidelights, and areas close to the floor. Extremely durable, this JELD-WEN Twenty Minute Fire Rated 6-Panel Primed White Steel Prehung Front Door with Brickmould will enhance your entryway. A 3/4-hour rated door is found in walls of corridors and room parti-tions. CDF offers a single 90 minute fire rated wood door made of mineral core materials which is suitable for room and corridor partition openings where rated doors are required. GENERAL REQUIREMENTS . Commercial fire rated door requirements are typically determined by the fire rating of the wall and use of the door. Fire rated doors and frames are covered, including a chart of the minute/hour ratings, maximum glass size, and other requirements. These time-based tests are based on the timed exposure of flames the door and assembly can handle; examining the hardware, wall and door assembly as written in the building code standards. Simpson 20-minute fire-rated doors comply with major code requirements for the 20-minute fire safety classification. These requirements apply to all fire rated doors, frames, and windows. Some fire rated doors, such as 20 minute doors in fire resistance rated corridors or smoke barriers, may also require testing for smoke infiltration under UL 1784, Standard for Air Leakage Tests of Door Assemblies and Other Opening Protectives. It is properly referred to as a 20 minute fire rated door "assembly" which would include the frame and associated hardware all of which would be included in the door "assembly" This comes from the NFPA 80 Standard which is the authority standard for testing of fire rated door assemblies.