What is Thermal Performance Requirements of Immersion suit as per SOLAS ?

Thermal performance requirements for immersion suits :- 

(a) An immersion suit made of material which has no inherent insulation shall be :- 

1. Marked with instructions that it must be worn in conjunction with warm clothing; and 
2. So constructed that, when worn in conjunction with warm clothing, and with a lifejacket, if the immersion suit is to be worn with a lifejacket, the immersion suit continues to provide sufficient thermal protection, following one jump by the wearer into the water from a height of 4.5 meters to ensure that when it is worn for a period 1 hour in calm circulating water at a temperature of 5 degree C, the wearer’s body core temperature does not fall more than 2 degree C.

( b) An immersion suit made of material with inherent insulation, when worn either on its own or with a lifejacket, if the immersion suit is to be worn with a lifejacket, shall provide the wearer with sufficient thermal insulation following one jump into the water from a height of 4.5 meters to ensure that the wearer’s body core temperature does not fall more than 2 degree C after a period of 6 hours immersion in calm circulating water at a temperature of between 0 degree C and 2 degree C. 

(c ) The immersion suit shall permit the person  wearing it with hands covered to pick up a pencil and writ after being immersed in water at 50 C for a period of 1 hour.