The extract below featured in a national newspaper. It’s not clear if swimming pools operators are classed as professional users or not. I suspect they’re not. It doesn’t matter. It should jolt the consciences of pool operators into action, those still using unnecessarily strong acids for pH control. PWTAG guidance is that acids should be purchased, stored and used in strengths of less than 15 per cent.
Possessing potentially lethal acid without a licence is now a criminal offence, with offenders facing a two-year prison sentence.
Since 1 July, members of the public wishing to import, acquire or, use sulphuric acid above 15 per cent concentration have been required to have a Home Office licence. Applicants need a legitimate purpose for a licence and must disclose any relevant health issues and previous criminal offences.
From 1st Nov 2018 individuals who are in possession of sulphuric acid, above a concentration of 15 per cent and without a licence, should dispose of the substance according to the manufacturer’s instructions or face prosecution.
The crime minister Victoria Atkins, said: “Acid attacks are utterly appalling crimes … We are taking this threat seriously and are making it harder to possess and purchase corrosive substances.” Professional users do not need a licence providing they are using the sulphuric acid for their trade.
Acids can be very nasty, exceedingly dangerous stuff. There are not only problems in handling, there are also problems of security! How secure is your acid store?
PWTAG has long been promoting a change of thinking, a move towards a safer alternative that is also good for water quality. So why shouldn’t pool operators use it? This is the message in our latest technical guidance note on choosing acids.
It lists the various methods available but is prefaced by a reminder to operators that they have a legal duty to use the safest, suitable chemical. Effective and least damaging. Operators who ignore this do so at their peril. Some do though! And go for the cheapest, nastiest alternative to the detriment of their pool water and safety.
Healthy pool water enjoys being treated gently with care and respect. Not shock dosed with acids and disinfectants that bounce it from one state to another and on the way give rise to the creation of nasty by-products and smelly chloramines.
Real advantages in safety and water quality
CO2 is the safest and gentlest acid, not suitable for all pools, but where it can be used there are very real advantages in safety and water quality.
Hydrochloric acid does the job but is hazardous in strong solutions. It’s much less of a hazard when supplied and used in strengths below 15 per cent.
Sodium bisulphate mixed to a 10% solution is relatively easy to handle. Yes, it will increase sulphate levels. So, monitor them regularly and dilute accordingly.
Sulphuric acid in high strength is the most dangerous. Potentially lethal, it can cause frightening skin burns like no other. Hence the Home Office controls announced above.
When mixed with water, concentrated sulphuric acid has a vigorous exothermic reaction (i.e., producing heat) and produces significant fumes over and above the background fuming of hydrochloric acid. It reduces alkalinity much more rapidly than hydrochloric acid. It leaves a sulphate residue in the water requiring sulphate concentration to be monitored. PWTAG recommend that the maximum strength this should ever be supplied to pools below 25 per cent. Below 15 per cent seems even wiser and safer given the new requirements.
Hydrochloric acid can be purchased at 5 per cent w/v strength and is ideal for use in hydrotherapy, holiday camps, small pools in hotels, fitness clubs and school pools. There is no fuming and far fewer handling issues and you don’t need a licence!
The suppliers will provide you with the strength you need to be both effective and safe. You just have to ask.
Ralph Riley; 14 November 2018
(Ralph Riley is the Vice Chairman of PWTAG, former Chief Exec of ISRM and provider and operator of many public swimming pools. He heads up the UK BSI representation on European and World sports standards. This blog represents Ralph’s views and not necessarily those of PWTAG.)