Foundry Protection - Standards

International Standard for Foundry Protective Clothing


The international standard most commonly used around the world for protective clothing for furnace operators is ISO 11612 Protective clothing - Clothing to protect against heat and flame.


This International Standard specifies performance requirements for protective clothing made from materials, which are designed to protect the wearer's body, except the hands, from heat and/or flame. For protection of the wearer's head and feet, the only items of protective clothing falling within the scope of this International Standard are gaiters, leggings, hoods, and overboots. However, concerning hoods, requirements for visors and respiratory equipment are not given.


The performance requirements set out in this International Standard are applicable to protective clothing which could be worn for a wide range of end uses, where there is a need for clothing with limited flame spread properties and where the user can be exposed to radiant, convective, contact heat and/or to molten metal splashes.

ISO 11612:2015
A1 or A1 + A2, B(x), C(x), D(x), E(x), F(x)

This Standard defines the minimum requirements for clothing for protection against heat and flames:


  • Clothing must be supplied with user information from the manufacturer.
  • Code A must be complied with.
  • At least one of the heat transmission performance codes B-F must be met.
A ISO 15025 Procedure A ISO
15025 Procedure B
Limited Flame Spread – Face Ignition
Limited Flame Spread – Edge Ignition
A1 OR (A1 AND A2) Pass
B ISO 9151 Convective Heat B1 to B3 B1
C ISO 6942 Radiant Heat C1 to C4 C1
D ISO 9185 Molten Aluminium Splash D1 to D3 D1
E ISO 9185 Molten Iron Splash E1 to E3 E1
F ISO 12127-1 Contact Heat F1 to F3 F1

Physical requirements including Tensile Strength, Tear Strength, and Seam strength must also be tested independently.

CODE A. Flame propagation (ISO 15025 method A) 

Sample is exposed to flame for 10 seconds then removed


Performance level X A1 A2
Average value of flame persistence < 2 s
Average value of residal incandescence < 2 s
not passed

CODE B. Convective heat (ISO 9151)

Temperature increase behind sample is measured


Performance level   B1 B2 B3
Heat Transmission Index - HTI (seconds) Min 4 10 20
  Max <10 <20  


HTI = Average of HTI12 and HTI2

HTI12 = Time to increase temperature by 12℃

HTI24 = Time to increase temperature by 24℃

CODE C. Radiant heat (ISO 6942 method B) 

Temperature increase behind sample is measured


Performance level   C1 C2 C3 C4
Heat transfer t24 (seconds) Min 7 20 50 95
  Max <20 <50 <95  


T24 = Time to increase temperature by 24℃

CODE D. Splashes of molten aluminum (ISO 9185)

Quantity necessary to damage PVC film is measured


Performance level   D1 D2 D3
Molten metal weight (grams) Min 100 200 350
  Max <200 <350  


Molten Aluminum at 780℃ (+/- 20℃) (1436℉) PVC film simulates human skin

CODE E. Splashes of molten cast-iron (ISO 9185)

Quantity necessary to damage PVC film is measured


Performance level   E1 E2 E3
Molten metal weight (grams) Min 60 120 200
  Max <120 <200  


Molten Cast-Iron at 1400℃ (+/- 20℃) (2552℉)PVC film simulates human skin

CODE F. Contact heat (ISO 12127) 

Heat transmission is measured


Performance level   F1 F2 F3
Threshold time (seconds) Min 5 10 15
  Max <10 <15  


Threshold time = time necessary to increase temperature by 10℃