NFPA 701: Standard Methods of Fire Tests for Flame Propagation of Textiles and Films

NFPA 701 (Standard Methods of Fire Tests for Flame Propagation of Textiles and Films) is an industry standard established by the National Fire Protection Association (NFPA) to evaluate the safety of “vertically hung” textiles and films regarding flame propagation. It is the most authoritative fire safety entry standard in North America for curtains, stage draperies, blackout blinds, and temporary shelter materials (such as tents) used in public spaces.

In the United States, whether it is a Broadway theater or a Las Vegas hotel, one of the first things the Fire Marshal checks during inspection is whether the hanging fabrics possess a valid NFPA 701 compliance certificate or label.

What is NFPA 701?

NFPA 701 is a set of test methods specifically designed for the flame propagation performance of textiles and films. Unlike fire resistance tests for building materials, NFPA 701 focuses on whether a material will burn rapidly, produce dangerous flaming droplets, and whether the flame will self-extinguish after being ignited by a small ignition source.

Note: NFPA 701 evaluates the “Flammability” of the material, not its “Fire Resistance” (the duration a material can block the passage of fire).

Scope: Which Products Require NFPA 701?

NFPA 701 applies to almost all flexible materials that are vertically hung or used for covering in public spaces. This is typically a mandatory requirement of local fire regulations (such as the IFC, International Fire Code).

• Interior Furnishings: Curtains, draperies, sheers, blackout linings.
• Stage & Performance: Stage curtains, backdrops, acoustic tapestries.
• Events & Outdoor: Event tents, tarps, large awnings, exhibition table skirts.
• Construction Materials: Temporary partitions, plastic films for construction.

Exclusions (Not Applicable):

• Upholstered Furniture: Fabrics for sofas and upholstered chairs do not fall under NFPA 701; refer to NFPA 260 or CAL TB 117.
• Wall Coverings: Wallpaper or acoustic panels glued directly to the wall usually require compliance with ASTM E84 (Class A/B), not NFPA 701.
• Carpeting: Floor covering materials are subject to ASTM D2859 or NFPA 253.

Test Methods Explained: The Logic Behind Choosing Method 1 vs. Method 2

NFPA 701 contains two distinct Test Methods. The choice of method is not based on client preference, but strictly depends on the density (weight) and composition of the fabric. Choosing the wrong method will render the test results invalid.

Method 1: Light & Single-Layer Fabrics

Method 1 is specifically designed to evaluate lighter, single-layer structures.

• Applicability Criteria: Fabric density ≤ 700 g/m² (21 oz/yd²).
• Typical Products: Curtains, sheers, light stage draperies, table skirts.
• Test Setup: 10 specimens (5 warp, 5 weft) suspended vertically in an open combustion chamber.
• Ignition Time: 45 seconds.

Method 2: Heavy, Coated & Multi-Layer Assemblies

Method 2 applies to heavy fabrics, fabrics with special coatings, and plastic films. This is a more rigorous testing environment.

• Applicability (High Density): Fabric density > 700 g/m² (21 oz/yd²).
• Applicability (Coated Fabrics): Such as blackout fabrics with vinyl backing. Regardless of weight, Method 2 is usually required.
• Applicability (Complex Structures): Multi-layer composite fabrics (sewn together), plastic films, and tent fabrics.
• Test Setup: Uses a large enclosed combustion cabinet. Specimens usually need to be hung folded (Folded specimens) to simulate the gathered state of actual curtains.
• Ignition Time: 70 seconds for folded specimens; 120 seconds for flat specimens.

Core Comparison: Method 1 vs. Method 2

Comparison Item	Method 1	Method 2
Primary Target	Light curtains, sheers, standard single-layer fabrics	Heavy draperies, coated blackout fabrics, tents, plastic films
Density Threshold	≤ 700 g/m² (21 oz/yd²)	> 700 g/m² (21 oz/yd²) (or coated materials)
Specimen Form	Hung Flat	Usually Hung Folded (or Flat)
Ignition Time	45 Seconds	70 Seconds (Folded) / 120 Seconds (Flat)
Key Pass/Fail Metric	Mass Loss	Char Length

Pass Criteria: How to Read the Test Report

To obtain an NFPA 701 certificate, the product must meet all the following criteria. Failure in any single aspect results in an overall failure of the test.

Method 1 Criteria

1. Mass Loss: The average weight loss of the 10 specimens after burning must not exceed 40%.
2. No Flaming Drips: Fragments or residues that drip to the bottom of the chamber must not continue to burn for an average of more than 2.0 seconds.
3. Afterflame: Although there is no mandatory failure standard, it is generally required that the average afterflame time does not exceed 2.0 seconds after the ignition source is removed.

Method 2 Criteria

1. Char Length: For folded specimens, the char length of any single specimen must not exceed 1,050 mm (41.3 inches).
2. Afterflame: The afterflame time of any single specimen must not exceed 2.0 seconds.
3. No Flaming Drips: Any drippings falling to the floor must not continue to burn for more than 2.0 seconds.

Key Regulation Comparison: NFPA 701 vs. CA Title 19 vs. EN 13501

While NFPA 701 is the “baseline” across the US, you may encounter other standards when sourcing globally or for projects in specific states (like California).

Standard	Region/Nature	Comparison Notes
NFPA 701	USA (National Standard)	The most common baseline. Focuses on mass loss and dripping. Accepted by most states.
CA Title 19	California, USA (Local Regulation)	Stricter. California often does not recognize certificates that are solely NFPA 701. It has extremely strict limits on char length and must be conducted by a California-registered laboratory.
EN 13501-1	EU (CE Certification)	Completely different system. Europe uses a classification system (e.g., B-s1,d0). NFPA 701 is simply “Pass/Fail”. They are generally not interchangeable.
BS 5867	UK	British curtain standard. Method 2 (Type B) is similar to NFPA 701, but test details differ, and they are not directly mutually recognized.

Expert Advice: If your product is to be sold throughout the United States, the safest strategy is to pass both NFPA 701 and CA Title 19 tests. This covers the strictest requirements across all 50 states.

Frequently Asked Questions (FAQ)