General Information and FR terms:
None of the current regulations governing the use of FR clothing specifically require the use of FR thread for embroidery applications. However, recommends the use of flame-resistant thread for embroidery or emblem attachments.
Commonly Used Terms
- Flame Resistant (FR) - A fabric or product that resists ignition and self-extinguishes after removal of the ignition source.
- Vertical Flame Test - A basic test that determines whether or not a fabric is FR by measuring how much of the fabric is consumed after 12 seconds of flame exposure.
- Arc Rating - The value for fabrics that describes their performance under exposure to an electrical arc discharge. Testing determines when the amount of exposure results in a 50% probability of causing the onset of second-degree skin burn. The arc rating is expressed in cal/cm2. It can be either an ATPV or an EBT.
- ATPV - The Arc Thermal Performance Value of a fabric shown in cal/cm2.
- EBT - The Energy of Breakopen Threshold. The cal/cm2 at which the fabric breaks open before it reaches its ATPV.
Protective Clothing Chart
| Hazard Risk Category or PPE Category | Clothing Description | Required Minimum Arc Rating of PPE Cal/cm2 |
|---|---|---|
 | Arc-rated FR Long-sleeve shirt and FR pants or FR coverall. | 4 |
 | Arc-rated FR Long-sleeve shirt and FR pants or FR coverall. | 8 |
 | Arc-rated FR Long-sleeve shirt and FR pants or FR coverall, and arc flash suit selected so that the system arc rating meets the required minimum. | 25 |
 | Arc-rated FR Long-sleeve shirt and FR pants or FR coverall, and arc flash suit selected so that the system arc rating meets the required minimum. | 40 |