STA POOL PLANT – HOT TUB SAFETY

Hot Tubs – The Risks Following The Lockdown Sales Boom In this article Luke Griffiths STA’s Qualification Development Manager for Pool Plant discusses some of the considerations and risks as a result of the boom in hot tub sales over the last 12 months

W

ith summer on the horizon, many Brits who contributed to the 1,080% rise in hot tub sales on eBay in 2020, compared to 2019, will be dusting off the covers and getting into 2021’s finest swimwear ready to take a long hot soak. The emergence of the inflatable hot tub alternative has made this luxury item accessible to the vast majority of UK residents and last year’s lockdown accelerated the demand. This issue’s article takes a brief look at the associated risks and methods for managing hot tubs in a business setting safely, but much of this is applicable to domestic hot tubs too.

RISK ASSESSMENT Due to the obvious hazards in the operation of hot tubs, a risk assessment must be carried out, including but not limited to: • Entrapment and entanglement • Drowning • Chemical dosing • Bacterial infection. HSG282 ‘The control of Legionella and other infectious agents’ is an essential guidance document by the HSE primarily for those who manage or operate spa pool systems and it explains how to manage and control the risks from legionella and other infectious agents. When developing risk assessments and safe operating procedures for spas and hot tubs, ensure this guidance is utilised. PWTAG also have a book dedicated to hot tubs for business containing some really useful information.

UNIQUE PROBLEMS ASSOCIATED WITH HOT TUBS There are a number of specific challenges when it comes to the effective sanitisation of hot tubs: • Due to aeration and agitation, there will be potentially zero visibility in the water. • Due to the low water content, it is easy to overdose chemicals. • Agitation of the water and its high temperature will cause disinfectant loss.

• Aeration of the water will commonly cause the pH to rise. This is due to water being able to absorb gases until saturation point is reached. Any further gases will then be released from the water. Amongst them will be the carbonate gases including CO2. • CO2 is generally added to lower the pH. Therefore, if CO2 is removed, the pH will invariably climb. • It is likely that there will be two water circulation systems, with the secondary system providing the supply to the water therapy jets. • Ratio of bathers to water volume will be extremely high. • Higher operating temperatures will increase risk of bacteriological growth. Some hot tubs operate at 37°C which should be risk assessed. Higher operating temperatures will cause higher release of bodily fluids, perspiration, fats etc. High temperatures will ‘burn-off’ body fats and cosmetic oils. In any event, higher temperatures up to and above 37°C can provide an excellent temperature for bacteria to multiply. • The risk of biofilm formation in poorly maintained hot tubs is great and particularly for inflatable hot tubs, there is an additional risk of biofilm formation as a result of having awkward to clean areas and the difficulty posed by drying between uses. For the reasons above it is important that water in hot tubs is treated and monitored just as closely as swimming pool water. For hot tubs used in a business setting, the recommended chemical parameters are: • Free chlorine levels between 3-5mg/l • Combined chlorine levels should be kept as low as possible, less than half the free chlorine level and no higher than 1.0mg/l • Total active bromine 4 –6 mg/l • pH between 7.0 and 7.6 (the closer to 7 the better). Furthermore, we need to address the problem of higher relative use by bathers and the

It is, of course, essential that all staff involved in the operation of hot tubs are trained to recognise industry standards, with appropriate risk controls strictly adhered to” www.swimmingpoolnews.co.uk 39_SPN_April_2021_STA.indd 39

higher use of chemicals. One of the items to consider is dilution with fresh water; this is often neglected or ignored which can lead to: • A high level of dissolved chemicals • Fats and oils fouling the filter • Reduction in efficiency of the disinfectant • In bromine dosed spas, high dimethyl hydantoin levels leading to ‘Bromine Itch’. For hot tubs used for business, the total volume of water should be replaced after each group of users or at least weekly – whichever is shorter. It is good practice when refilling to dose to 5mg/l free chlorine in the filled hot tub so the pipework and fittings get a shock dose of disinfectant and the hot tub is not full of unchlorinated water. It is, of course, essential that all staff involved in the operation of hot tubs are trained to recognise industry standards, with appropriate risk controls strictly adhered to. Those carrying out a risk assessment of a hot tub or similar should have the necessary experience and knowledge to do so. STA’s Level 3 Award in Pool Plant Operations qualification – which is CIMSPA professionally endorsed – covers all that operators need to ensure safe, clear and hygienic water practices in pools, spas and interactive water features – very relevant to hot tubs. BISHTA also offers a range of workforce training courses, including Water Hygiene Management training, which are available to non-members and are a membership stipulation. As BISHTA’s logo strapline highlights, the association’s principal focus is to ‘Promote Safe Hot Tub Standards’. Having the right equipment and the correct water hygiene management and maintenance regimes in place is vital. Safety Training Awards 01922 645097 www.safetytrainingawards.co.uk

SPN April 2021 39 28/04/2021 22:36