SV31 - Supervision During Thunderstorms (Lightning)

Purpose

To provide guidance on safe practice for the supervision of swimming pools during thunderstorms and lightning conditions.

Background

The presence of lightning around swimming pools is a safety risk.

Every year, lightning strikes kill an average of two people per year in Australia and injure 20 people per year. Summer is the peak season for outdoor and water-related activities, and when most lightning deaths and injuries occur. Vulnerable locations include: beaches, swimming pools, diving boards, lifeguard stands, and nearby outdoor recreational facilities.

Swimming pool facilities are connected to a large surface area via underground water pipes, gas lines, electric and telephone wiring, etc. Hence, lightning strikes to the ground anywhere on this metallic network may cause shocks elsewhere.

Aquatic facility owners and operators should implement appropriate safety measures during thunderstorms and lightning conditions.

There are a number of factors that need to be considered, such as the surrounding environment and structures.

Notes:

• Australian Standard 1768 recommends that indoor and outdoor pools should be treated the same with regard to lightning dangers, however, it has been industry practice to evacuate only outdoor pools so far, and there are no known incidents involving lightning strikes and electrical injury to users of indoor aquatic facilities.
• Standards Australia has advised that if an indoor pool is within a substantial structure which is generally earthed by virtue of its construction, the natural elements of the pool’s covering building would act as a lightning protection system. Then only testing would be needed to prove the structure is earthed and bonded in accordance with the AS1768.
• A “flash-to-bang” measurement of approximately 30 seconds indicates that the lightning is 10km away. A measurement of 30 seconds or less requires that immediate action be taken.

Outdoor Swimming Pools

An outdoor swimming pool with spacious grounds, may pose a greater risk in lightning conditions. If there are structures such as diving towers, precautions should be taken. For example, the erection of a lightning conductor, higher than the dive tower, would reduce the likelihood of a lightning strike hitting the dive towers.

Where should people go for safety?

When outdoors, some of the measures for reducing the risk of injury that may be caused by lightning strikes to ground during a local thunderstorm are as follows:

• Ask patrons to exit the water and move to an identified safe place
• Ideally, seek shelter inside a large building or a motor vehicle keeping away from, and getting out of wide, open spaces and exposed hilltops
• Do not shelter beneath tall or isolated trees, it has been estimated that one in four people struck by lightning are sheltering under trees
• Do not touch or stand close to any metallic structures, including wire fences and clothes lines
• Do not carry metallic objects such as umbrellas or golf clubs and remove metallic chains and other jewellery, particularly from the head and upper parts of the body
• Do not shower or use taps during thunderstorms

Indoor Protection

If the indoor pool building is equipped with a lightning and surge protection system installed in accordance with AS1768, there is no need to evacuate the pool during a thunderstorm.

Description

Evacuation

The closure of the swimming pool should be undertaken when lightning is within 10km of the facility.

Use the "flash-to-bang" method, by measuring the time between a lightning flash and the thunderclap, to estimate the distance away of the thunderstorm.

When lightning is less than 10km away, people occupying the pool and pool surrounds should be evacuated to a covered area, which provides sufficient electrical earthing for a lightning strike. Gazebos, marquees and trees are not sufficient protection from lightning strikes.

Resuming Pool Activities

According to the National Lightning Safety Institute more lightning originates from the back edge of a thundercloud than from the front side, making recreation activity resumption decisions difficult. Managing the risk of lightning strikes, therefore, requires a cautious and conservative approach.

Once lightning has moved greater than 10km away or has subsided, people may return to normal activity. As a general rule, pool activities should remain suspended until thirty minutes after the last thunderclap is heard.

Staff should continue to monitor the weather for changes as storm activity could return.

Electrical Equipment

Electrical equipment should not be used during electrical storms.

The use of portable, battery-powered PA systems (e.g. loud hailer) may be considered when the storm is very close, since fixed-installation PA systems may be struck by lightning.

Telephones should not be used during electrical storms.

First Aid

Anyone struck by lightning should be rescued as soon as it is safe to do so.

The safety of the rescuers should be considered.

The casualty should be moved to a covered area, assessed and treated.

In the first aid treatment of a patient injured by lightning, it is essential that CPR be provided to patients who are not breathing.

Monitoring

If there are area weather warnings issued, they should be monitored by radio or telephone, if and when safe to do so.

Detailed monitoring is available through the Bureau of Meteorology in each State and Territory.

Management Activities

Review and update emergency management plans

Ensure regular weather monitoring

Identify lightning-safe locations at the facility, consider designating these locations with signage

Determine how patrons will be notified and managed during electrical storms, as well as procedures for resuming activities

Educate staff through in-service training and emergency procedure training

Inform stakeholders such as councils, pool hire groups and contractors as to the facilities procedures

Update first aid procedures and operations manuals (where relevant)

References / Further Information

• AS/NZS 1768:2021 – Lighting protectionKithil, Richard. Lightning and Aquatic Safety: A Cautionary Perspective for Indoor Pools. National Lightning Safety Institute. Cited 24/2/2004 at http://www.lightningsafety.com/nlsi_pls/indoor_pools.html
• Standards Journal 2, 2004, Lifesaving Society, Toronto
• University of Western Australia (2015). Fact Sheet: Lightning. Perth
• Advisory Council on First Aid, Aquatics, Safety and Preparedness. Lightning Safety for Outdoor and Indoor Pools. American Red Cross.
• International Life Saving Federation (2014) Lightning. International Life Saving Federation, Belgium
• National Weather Service, National Oceanic and Atmospheric Administration: http://www.lightningsafety.noaa.gov/index.htm
• National Weather Service, National Oceanic and Atmospheric Administration: Lightning Safety http://www.lightningsafety.noaa.gov/resources
• Royal Society for the Prevention of Accidents (UK). Lightning at Leisure, Leisure Safety, Advice and Information http://www.rospa.com/leisuresafety/adviceandinformation/leisuresafety/lightning.aspx
• Australian Bureau of Metrology, Severe Thunderstorms: Facts, warnings and protection http://www.bom.gov.au/info/thunder
• Canadian Centre for Occupational health and Safety http://www.ccohs.ca/oshanswers/safety_haz/lightning.html
• Makdissi M, Bruckner P, ‘Recommendations for Lightning Protection in Sport’ MJA 2002 177 910 pp35-37 http://www.peterbrukner.com/wp-content/uploads/2012/07/60.-Makdissi-Brukner-MJA-Lightning.pdf
• Surf Life Saving Australia Policy 2.2 ‘Lightning’ July 2006 http://sls.com.au/downloads

Previous Versions

• Guideline SV31 SUPERVISION DURING THUNDERSTORMS (LIGHTNING), Issue 3, Jan 2018
• Guideline SU25 Supervision During Thunderstorms, Issue 2, Nov 2005
• Guideline SU22 Supervision During Thunderstorms, Issue 1, Sep 1999