PR97™ Data



Protection Against

Flame Spread EN 532, Radiant Heat EN 366, Convective Heat EN 367

Molten Metal Splash EN 373

Electric Arc ASTM F1959-99

Criteria

Fabric Weight

265gsm/7.5oz

Fabric Weight

320gsm/9.3oz

Fabric Weight

380gsm/11.2oz

Fabric Weight

500gsm/15.0oz

Tensile Strength

ISO 5081-1977(E)

Warp (min):

600 N (134 lbf)

Weft (min):

500 N (112 lbf)

Warp (min):

700 N (157 lbf)

Weft (min):

600 N (134 lbf)

Warp (min):

675 N (151 lbf)

Weft (min):

775 N (174 lbf)

Warp (min):

1100 N (245 lbf)

Weft (min):

1100 N (245 lbf)

Tear Strength

ISO 4674-1977(E)

Warp (min):

20 N (4.5 lbf)

Weft (min)

20 N (4.5 lbf)

Warp (min):

25 N (5.5 lbf)

Weft (min)

25 N (5.5 lbf)

Warp (min):

27 N (6.0 lbf)

Weft (min)

27 N (6.0 lbf)

Warp (min):

40 N (9.0 lbf)

Weft (min)

40 N (9.0 lbf)

Dimensional Change

ISO 5077: 1984

Warp (max): 3%

Weft (max): 3%

Warp (max): 3%

Weft (max): 3%

Warp (max): 3%

Weft (max): 3%

Warp (max): 3%

Weft (max): 3%

Flame Spread1

EN 532: 1992

A

A

A

A

Radiant Heat2

EN 366: 1993

(20kw/m2)

C1

C1

C1

C1

Convective Heat3

EN 367: 1992

B1

B1

B2

B2

Metal Splash4

Molten Aluminium

EN 373: 1993

 

D1

 

D2

 

D2

 

D2

Metal Splash4

Molten Iron

EN 373: 1993

 

E1

 

E2

 

E3

 

E3

ATPV (cal/cm2)5

NFPA 70E HRC

 

ATPV (Ebt)6 (cal/cm2)

NFPA 70E HRC

4.4

1

 

 13.0

2

6.1

1

 

 11.0

2

 

1

 

 

 

 

7.5

1

 

 19.0

2

 
  • 1 Flame Spread (EN 532:1992) - A single layer or multi-layer system is tested by face ignition. Limited spread of flame of the specimen is determined when a calibrated flame is applied to the surface of the vertically oriented specimen for 10 seconds.
    • Pass A - no flaming to edge, no hole formation, no flaming debris, mean afterflame ≤ 2 seconds, mean afterglow ≤ 2 seconds. 

  • 2 Radiant Heat (EN 366:1993) -  A thermal sensor is mounted behind and in contact with the specimen, which is in front of a radiator. The rise in temperature (as recorded by the sensor) over time at a given level of incident radiant source is measured. Time for reaching threshold of pain (t1) and second-degree burn (t2) is calculated for classification. The following classifications are performed:

    • Changes in appearance of fabric, e.g., shrinkage, charring, discolouration, scorching, melting, dripping and glowing.

    • Heat transfer levels (t1, t2) and heat flux (t3).

    • Heat transmission factor - a measure of the fraction of heat transferred through a specimen.

    • Classification:

      • Level t2,  Seconds

      • C1           8 - 30

      • C2           31 - 90

      • C3           91 - 150

      • C4           151 +   

  • 3 Convective Heat (EN 367:1992) - Heat transmission through FR clothing depends on the thickness, type of fibres used and the textile's composition (blend, weight). Air gaps between layers (with undergarments, or in multi-layer systems) can also affect heat transmission. In this test, a horizontally oriented specimen is subjected to a gas flame from a gas burner beneath it. The heat passing through the fabric is measured by means of a calorimeter. The rise in temperature to 24° C/75° F (HTI 24) is recorded in seconds for classification.

    • Classification:

      • Level      HTI

      • B1          3 - 6

      • B2          7 - 12

      • B3          13 - 20

      • B4          21 - 30

      • B5          31 + 

  • 4 Molten Metal Splash (EN 373:1993) - Single layer and multi-layer fabrics are tested by pouring measured quantities of molten metal at a specific angle onto the test specimen. The damaged is assessed by placing a PVC film (having similar qualities to human skin) underneath the test specimen and noting damage after pouring. Any adherence of metal to the specimen is noted. Classification is done on the basis of the minimum quantity of molten metal required to cause damage to the PVC film.

    • Classification: Molten Aluminium Splash

      • Level     Grams

      • D1         100 - 200

      • D2         201 - 350

      • D3         351 +

    • Classification: Molten Iron Splash

      • Level     Grams

      • E1         60 - 120

      • E2         121 - 200

      • E3         201 + 

  • 5 Arc Thermal Performance Value (ATPV)

    • Test Standards:

      • USA:

        • ASTM F1959-99 - Standard Test Method for Determining the Arc Thermal Performance Value of Materials for Clothing.

        • ASTM F1506 - Standard Performance Specification for Flame Resistant Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards.

        • NFPA 70E - Standards for Electrical Safety in the Workplace. 

      • European:

        • ENV 50354 - Electrical Arc Test Methods for Material and Garments, for Use by Workers at Risk from Exposure to an Electric Arc. 

  • 6 Ebt - Energy break-open threshold, refers to ATPV test results when PR97™ is used in conjunction with 100% Cotton Undergarments (265gsm with 6.8oz/230gsm, 320gsm with 4.5oz/152gsm and 500gsm with 4.5oz/152gsm). The break-open threshold is evidenced by the formation of one or more holes (break-open) in the fabric, which may allow thermal energy to pass through.    


 

ASTM F1959-99

Arc Thermal Performance Value (ATPV)

Test Method

ASTM F1959-99 Standard Test Method for Determining the Arc Thermal Performance Value of Textile Materials for Clothing by Electric Arc Method Using Instrumental Sensor Panels 

Fabric Weight

gsm/oz

Over

100% Cotton

T-Shirt gsm/oz

ATPV

cal/cm2

HAF

(%)

315/9.3oz (a)

330/9.7 (b)

 

6.1

71

315/9.3 (a)

330/9.7 (b)

142/4.2

11 (Ebt)

84

510/15.0 (a)

480/14.2 (b)

 

7.5

78

510/15.0 (a)

480/14.2 (b)

142/4.2

19

88

254/7.5 (a)

275/8.1 (a)

 

4.4

64

254/7.5 (a)

275/8.1 (b)

230/6.8

13 (Ebt)

85

 

  • (a) Reported Weight

  • (b) Average of Samples Measured

  • 100% Cotton T-Shirt – is recommended, because although it may burn in an arc accident, it will not melt and drip and adhere to the skin as a poly/cotton fabric would.

Key Definitions

  • Arc Rating: a term used to indicate the protection level of a garment.

  • Arc Thermal Performance Value (ATPV): the incident energy on a material that results in sufficient heat transfer through the material for a 50% probability of the onset of a second-degree burn injury. 

  • Calorie: is the energy required to raise one gram of water one degree C.

  • Energy Break-open Threshold (Ebt): The amount of energy needed to cause the material to break-open. The arc rating of a fabric is equal to its ATPV or its Ebt (in cases where the Ebt is lower than the ATPV or no ATPV can be determined). 

  • Heat Attenuation Factor (HAF): the percent of arc flash heat energy blocked by the material.