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 m, to ensure that when it is worn for a period of 1h in calm circulating
water at a temperature of 5°C, the wearer's body core temperature does not fall more
than 2°C.