A major concern in finding a fabric appropriate for theatrical use is fire retardancy. Many materials come flame retardant from the mill; others can be treated later. Still others, primarily synthetics and those containing metallics, cannot be flame proofed at all.

FR / Flame Retardant

FR Fabrics are woven with threads that are not initially considered fire retardant. The woven product is treated with a flame proofing compound through immersion to make it fire retardant. The flame proofing compound adheres to the outside of the fibers, but is water soluble. Painting, washing or dry-cleaning the material can remove the compound and void the fire retardancy. Even excessive humidity can have this effect over time. The fabric can be flame proofed again by spraying a flame proofing solution on to the backside of the fabric. A yearly field test to check the status is recommended.

IFR / Inherently Flame Resistant

IFR Fabrics are manufactured from polyester yarns to meet NFPA 701 testing protocol without any additional treatment. These fabrics are expected to retain their IFR properties for the life of the material, however, this cannot be guaranteed(see additional information below). Conditions of use including time, humidity, excessive dust or dirt etc. may adversely affect the flame retardant capabilities. A yearly field test to verify the status is strongly recommended.

DFR / Durably Flame Resistant

DFR Fabrics are woven with threads that have some fire retardant qualities, but not necessarily enough to meet NFPA701 testing protocol. The material is treated with a chemical that chemically binds with the fiber composition rather than adhere to its surface. This chemical is not water soluble and is expected to withstand washing or dry-cleaning for an extensive period of time. As with IFR fabrics, however, conditions of use including time, humidity, excessive dust or dirt etc. may adversely affect the flame retardant capabilities. A yearly field test to verify the status is recommended.

NFR / Non-flame Resistant

NFR fabrics are woven with threads that are not fire retardant. They have not been treated, or cannot be treated.



Inherently Flame Resistant (IFR) fabrics are manufactured from a number of polyester yarns incorporating organic phosphorous compounds introduced into the molecular structure of the fiber. Fabrics produced from these fibers are manufactured to meet NFPA 701 testing protocol. When tested in the laboratory, the fibers in the fabric retract away from the flame not allowing the flame to spread.

These fabrics are expected to retain their IFR properties for the life of the material. However, it should be understood that IFR does not mean permanently flame proofed. Ambient conditions, cleaning practices, excessive dust build up, etc., can affect the fabric’s flammability characteristics. This is true of synthetic IFR fabric or any other cellulose constructed and chemically treated fabric. Proper care, cleaning, and periodic testing can maintain the proper characteristics.

Testing labs perform NFPA 701 tests with great consistency (with a sample and flame source under controlled conditions in laboratory setting). Field tests – as specified under NFPA 705 – can never be consistent as they depend largely on the current condition of the material and who is conducting the test. No fabric on the market today is manufactured to meet all the rigors of field testing. The official NFPA 705 Recommended Practice for Field Flame Test for Textiles and Films cautions and states: “There is no known correlation between this recommended practice and NFPA 701”.

NFPA 701 is widely accepted and a certificate of fire retardancy for the fabric or curtains you purchase attesting to compliance with the NFPA 701 testing protocol should be sufficient. However, each municipal fire department may have its own requirements that need to be met.

The New York City Fire Department, for instance, is now conducting field tests on many stage and auditorium curtains even when a certificate for NFPA 701 is present, and this might spread to other localities. Many theaters keep a testing sample of their fabrics at the site for field testing should it be necessary. When considering the investment of purchasing curtains made from IFR fabrics it is important to understand that though you probably will avoid the cost and inconvenience of re-treating your curtains each year – this cannot be guaranteed.

It is the obligation of every theatre to have their curtains field tested annually so that any problems can be dealt with before they develop. We also recommend regular brushing and vacuuming as part of theater maintenance.

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