In this week’s New Scientist (2 March 2019) there are a couple of interesting replies to a question from a reader working in catering.

The reader comments that she often gets burns on her hands which she says are minor, but painful. She has sought the advice of the NHS (see Burns and Scalds) which includes the suggestion to hold the burn under a running tap of cool water for 20 minutes – and then not to cover it with anything greasy.

Health & Safety penalties now on risk rather than accident

I’d be asking her employers Health & Safety questions – the word ‘often’ is worrying – see the HSE website for advice regarding the hospitality industry. Those readers who are owners, employers, directors may be interested to know that as a result of recent legislation Health & Safety penalties are based on harm risked NOT the actual injury. And NOT just the potential risk to the individual, but to ALL employees possibly at risk. DFS was recently awarded a penalty of £1m.

But the letter writer was more interested to know why 20 minutes exactly? She points out that it’s the transfer of energy from one substance to another which causes the burn, and even a hot oil burn doesn’t take that long to cool.

Why keep going with the cool water for 20 minutes

The first respondent, Jane Lilley of Dorking, commented that the length of time the cool water needed to be applied depended on the severity of the scald or burn: the substance; the quantity; and how quickly the healing water reached the wound.

One important aspect is the depth of the burn. In the case of a more serious burn the heat will penetrate down before you can begin to cool the skin on top. You will be cooling the surface, but the heat will continue to penetrate. Therefore – keep going, she advises, for 20 minutes.

Why use cool water, and not cold water or ice

The second respondent, Vittoria Dessi from London, agrees, and adds that it is also better to use cool, rather than cold water. The reason for this is that if the water is too cold the skin may become numb – its sensitivity is compromised. It may feel as if the heat has been taken out of the burn when it has not. The cold temperature may also result in the blood vessels constricting and thereby restricting blood-flow which is aiding the healing process. Obviously, ice is even more damaging than very cold water.

Why all this is particularly important when it comes to steam scalds

Some fascinating research regarding scalds caused by steam was published on the Science Daily site last May. Hot steam is particularly vicious because it quickly penetrates the upper skin layers (the epidermis) to damage the lower layers (the dermis) – initially it doesn’t look serious, when in fact it is. Once the steam reaches the sensitive dermis it condenses, causing a lot more harm. The epidermis provides protection against dry burns, but it’s because the epidermis’ pores are larger than water molecules that the steam just, well, steams through.

The deeper levels of the skin take longer to release heat so the cooling healing process needs to be prolonged.

• act quickly
• use cool, not cold water
• keep at it….20 minutes if possible
• don’t cover with grease – this can introduce infection

If there is any doubt always seek the advice of a doctor.