Geophysical survey risks due to hot weather

The effects of climate change are becoming very apparent within the UK and of particular concern to geophysical surveyors are summer peaks of heat and humidity. This week we are yet again having to avoid survey in temperatures well above 30C in the south of England and this is exacerbated by high humidity. Combined with poor surface conditions and the enforcement of inappropriate PPE by some companies, then the effects can put the health and safety of surveyors at risk.

In an attempt to provide clients with a visual indication of how various factors combine with temperature to increase risk of overheating, we drew up a simple table with some basic colour coding to highlight risk within columns that consider survey in good ground conditions and low humidity, good ground conditions with high humidity, poor ground conditions with low humidity and poor ground conditions or inappropriate PPE with high humidity (PDF link).

There are numerous other factors one could introduce such as physical fitness and age but it would become quite complex so it relies heavily on our experience and may or may not be representative of other companies and individuals. We feel there is quite a rapid increase in risk between air temperatures in the low 20s C and high 20s C which increases significantly with high humidity, poor ground conditions or inappropriate PPE. With air temperatures above 30C, survey is generally abandoned as risk becomes much higher and increasing breaks and fluid intake does little to lower body temperature for long enough to allow safe survey to continue.

Physical effort involved in survey can vary significantly so paced surveys using handheld equipment may be more demanding than using ATV towed arrays; however, ATVs can become extremely hot at low speeds so that parts of the operator are subject to much higher temperatures, in general we find that the potential for overheating is broadly similar. Yes there will be those with air conditioned vehicles etc. but I would guess this is rare in the UK.

It is hoped that by providing a basic colour-coded assessment of risk then this will assist in making sure survey is carried out at appropriate times of day, avoids summer heat spikes and high humidity, considers problems associated with poor surface conditions and allows surveyors to determine appropriate PPE given the site conditions they are likely to encounter.

It is important to take on plenty of fluids during high temperatures but this can be particularly effective if it is chilled, simply changing to vacuum flasks containing chilled water and/or ice is one simple way of providing cold fluids throughout the day. It's all pretty obvious stuff really but being prepared is the key to avoiding any problems. Overheating and heat exhaustion should be highlighted as of primary concern within RAMS for survey carried out at any time of year but the potential for periods where survey should be avoided is likely to increase within the summer months.