Flame retardant chemicals are typically liquid coatings, paint additives, or soaking sprays intended to slow or self-extinguish the spread of a fire before it gets out of control. It's important to note the terminology here. You may hear this referred to as 'flame-proofing', but that's technically incorrect, as it's not really possible to make anything actually flameproof in a complete way.
- 1 About
- 2 Collection of Online Articles about Proper FR
- 3 Affidavit of Flame Retardant Chemical Application, & the Certificate of Fitness
- 4 NFR vs FR vs IFR vs DFR
- 5 Synthetic and Natural Fabric Flame Retardants
- 6 How to apply Natural Fiber Flame Retardant to a muslin backdrop
- 7 Paint Additive Flame Retardants
- 8 Paper and Cardboard Flame Retardants
- 9 Intumescent Paints
- 10 Specialty foliage flame retardants
- 11 Is your FR product too old to use?
Most venues, events, and international tours have strict standards on the flame retardant properties of any scenery or decoration that comes into the space. However, these standards vary a lot from city to city, as each jurisdiction sets its own laws based on their own history of disastrous public fires. You can usually find them on your city's Fire Department website. As a starting point, if you know your project is touring to a stricter venue or overseas, you should assume that you should follow the most stringent applicable testing requirements you can find.
There is no single standardized flame-retardant treatment or coating method. Scenic artists must do thorough research to know which chemicals can be used on which substrates, and products often have limited regional distribution and sales areas. For example, soaking sprays of a natural fiber flame retardant may work well on a muslin backdrop, but will do nothing to prevent fire on a synthetic poly backdrop. In such a case, a synthetic fiber spray must be used, which creates a crystalline outer coating that does not soak in to the fabric.
Depending on the material being treated, the person or person(s) responsible for treating it, and the size of the task, methods will vary. Methods will also vary depending on which flame retarding chemical you are using. Several different types of flame retardant treatments are available; however, only a few are widely used because many of the treatments have undesirable properties. For example, some treatments change the color of the material and/or damage the material.
Water soluble treatments are the least expensive and are the most easily applied. However, they lose their effectiveness when washed or exposed to the weather. If you drop gets wet in any way, it can void the certificate. (Meaning that if you buy fabric that has been flame retarded and then paint on it, it's very likely going to need reapplication of chemicals before you can sell it to your buyer!) Some treatments lose their effectiveness when exposed to the solvents used in certain dry cleaning operations. Still other treatments have short lived effectiveness and should only be used for short periods of time. All certificates of application of flame retardant chemicals have limited warranty periods set by the chemical's manufacturer, typically in the vicinity of 3 years of effectiveness before requiring retreatment.
It is important to understand that not all materials may be treated to be flame resistant (e.g., hemlock, balsam, Spanish moss, and Christmas trees that contain pitch). In many cases, you may be required to remove these items from a venue if their presence is noted by a fire marshal.
All chemicals used during the flame-retardant chemical treatment process must be approved by the local Fire Department and have a Certificate of Approval Number. The manufacturer of the chemical or product used in the flame-retardant treatment must obtain such from the Fire Department.
Scenic Artists (especially those in larger cities) are more often than not responsible for flame retarding scenery since it may affect the look and feel of the end product. Again, scenic artists are strongly advised to do their own research on best practices for sourcing, applying, and testing materials that meet the standards of safety in their local area. As a starting point for this, here  is a link to the FDNY's study guide for C-15 Certificate Holders, outlining the scenarios you'll need to be aware of. Alternatively, contacting a company such as Turning Star  that specializes in flame retarding existing scenery and drops can be a great starting point for advice over the phone about which chemicals can accomplish which results in which circumstances.
Collection of Online Articles about Proper FR
When researching FR methods and practices a standard google search might not work - this is a place to share the articles and info we have all found.
- Stage Directions Feb 2009 " Theatre and Fire, an Unwelcome Association" 
- Burning Test for Fabric Identification 
Affidavit of Flame Retardant Chemical Application, & the Certificate of Fitness
Flame-retardant treatment must be conducted under the personal supervision of a Certificate of Fitness (C-15) holder. The C-15 Certification asserts that the holder is eligible to oversee the correct application and field testing of flame retardant chemicals. The Certificate of Fitness holder is responsible for making sure that the correct procedures are followed during the flame-retardant treatment process. The holder also performs a field flame test and when that is passed can issue the buyer of the finished product a Notarized Certificate of Flame Retardancy that they must then file with their local fire marshal. You do not have to be a Fire Department employee to be a Certificate of Fitness holder- meaning scenic artists can be one! Depending on where you work, it is useful and super easy to be a Certificate of Fitness holder. Check your local Fire Department for testing dates, locations, requirements, and fees.
NFR vs FR vs IFR vs DFR
- Not Flame Retardant (NFR): The material does not pass the flame field test and needs a chemical approved by the Fire Department to make it flame resistant.
- Flame Retarded (FR): The material has had a chemical applied to it that resists and delays the spread of flame. The material has passed the field test but washing or altering the fabric in any way will change its effectiveness and void the certificate of flame retardancy. Depending on the chemical, a material will generally be warranted flame retardant for 1 year and then will need to undergo another field test and receive another certificate.
- Inherently Flame Retardant (IFR): The material is flame retardant without a chemical being applied. It will remain flame retardant throughout it's life even with repeated washing. However, a field test is needed to verify.
- Durably Flame Retardant (DFR): Similar to IFR this material is flame retardant without a chemical being applied to it. It will remain flame retardant throughout it's life however certain chemicals can compromise its integrity. Hence it is labeled as "durably" rather than "inherently." Field test is needed to verify.
Synthetic and Natural Fabric Flame Retardants
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How to apply Natural Fiber Flame Retardant to a muslin backdrop
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Paint Additive Flame Retardants
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- Rosco Flamex PA 
This is a clear, un-pigmented additive for creating a flame retardant paint layer. Add one full jar of Roscoflamex PA to a US gallon (3.79L) of water based paint to make your paint coating flame retardant. Roscoflamex PA is compatible in most latex or vinyl acrylic paints but always test with your specific paint choice. Do not use Roscoflamex PA with metallic paints as the metal pigments may react and tarnish or corrode. Roscoflamex PA does NOT alter the flammability of the substrate being painted but only adds a retardant treatment that slows the spread of fire along the surface. Do not add this to a Plastic Varnish type of sealer - it will create some sort of crazy expanding clear paint, it will still work as a sealer, but it be wierd to work with, and will not pass a FR test.
Paper and Cardboard Flame Retardants
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- Rosco FLAMEX PC 
This can be sprayed on with a small pump sprayer like a P-50. Make sure to get a full coating, with no holidays. Roscoflamex PC was formulated specifically to treat the many paper products commonly used in props and scenery construction. Most paper products without a wax coating or other water resistant properties can be effectively treated. PLEASE NOTE: When treating thicker paper products like cardboard, foam core, gator board - only the outside layers of paper will be treated, not the inner core.
The key feature of intumescent coatings is that they expand when exposed to high temperatures, such as those found in fire. As they increase significantly in size they become less dense which acts as an insulator and slows the spread of flame. It works well for plastic materials that cannot absorb more liquid flame retardant chemicals. The intumescent paint acts like a barrier and seals the plastic off from the flame.
Flame Control Coatings This company has a wide variety of intumescent coatings that can be applied to wood, sheetrock, metals, fiberglass, composites, concrete, and polyurethane foam. Available in opaque colors as well as clear. Roll or brush on. As alway, please read the MSDS and take safety precautions when applying these coatings. 
Specialty foliage flame retardants
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Is your FR product too old to use?
Many times you walk into a shop and on a shelf in the back are some dust covered bottled of FR and know one knows how long it has been there. In many circumstances the products have a fairly long shelf life, but they do go bad - but how do you know? Look for crystal chunks. If your shake the bottle and see floaters the odds are good that it has expired, and you will need to just dispose of it properly.