A cold room door can be shut from outside, the insulated walls keep sound in, and someone without proper clothing gets into trouble quickly at sub-zero temperatures. A warning sign reminds people of that risk. What actually gets a person out is an inside release, an alarm that someone outside hears, and a way of working that shows who is inside.

EN 378-1:2016, the safety standard for refrigerating systems, groups these measures in its informative Annex D, written for rooms that operate below zero. Under D.2 it must be possible to open the door from inside and from outside at all times. For rooms larger than 10 m³, D.3 lists:

  • an alarm worked by illuminated push buttons or hanging chains near the floor, giving an audible and visible signal where someone is always present, which can only be silenced by a deliberate action
  • a signal circuit of at least 12 V, with a battery that lasts at least 10 hours and is kept charged automatically from the mains
  • lighting switched on from inside that cannot be switched off from outside, and fans stopped from inside that cannot be restarted from outside
  • illuminated switches, permanent emergency lighting, and independent lighting that marks the way to the exit if the lights fail

In Turkey the binding rule is the Regulation on Health and Safety Measures in Workplace Buildings and Annexes (Official Gazette 17 July 2013, No. 28710). Annex 1, item 35(e) requires doors on escape routes to open from inside at any time without help, and item 10(ç) and (d) require emergency exit doors to open easily and never be locked or tied. Item 20 makes the employer responsible for protecting staff who have to work continuously in very cold conditions.

The sign at the entrance states that the door is not locked while anyone is inside, shows where the release handle and alarm button are, and gives the clothing and maximum working time for a freezer room. That time limit comes from the risk assessment, based on room temperature, task and clothing. Because the inside release is never used in normal work, nobody notices when it fails. Each week the door is opened and closed from inside, the alarm button is pressed to check where the signal is heard, and the result goes with the date on a sheet fixed to the inside of the door. Where people work alone, whoever goes in writes their name and time on a board at the door and wipes it off on the way out.