Leighton’s Heat Stress Management Plan

In mid 2012, Leighton Contractors commenced a 2 year project constructing water treatment facilities and storage ponds for Australia Pacific LNG. The project is split across two sites at Condabri and Reedy Creek in Queensland, where it employs up to 800 FIFO workers, many of whom are exposed to air temperatures in excess of 45ºC degrees and radiant temperatures of 57ºC degrees on a daily basis.

Due to the geographic location of the project and the physically demanding nature of the work involved, project manager Simon Lewis and his team of safety experts identified dehydration and heat stress as a critical risk from the outset. They brought in external health professionals 4CRisk and Remote Area Paramedic Neil Hokins and set themselves the target of ‘zero heat stress related incidents’ for the duration of the 2 year project.

The result was a unique and innovative Heat Stress Management Program that has to date not only achieved this goal, but has recently received the Queensland Project Safety Excellence Award for outstanding contributions and innovation in on-site safety. The following are some highlights of the program that were key to the project’s success.

Redefining ‘Fitness for Work’

Traditionally ‘fitness for work’ has been measured solely in terms of drug and alcohol compliance. As part of their Award Winning Heat Stress Management Program, Leighton’s broadened this line of thinking to include ‘hydration compliance’.

Throughout their shifts, Leighton’s workers are randomly selected and tested to monitor their hydration status. If he or she fails the test, the accountable supervisor is notified and the worker must cease work and commence drinking small amounts frequently for one hour, or until such time as he or she passes the re-test and is deemed sufficiently rehydrated.

Working Zones and the ‘Thermal Work Limit’ (TWL)

The Thermal Work Limit (TWL) measures the maximum safe work rate for the environmental conditions present at a worksite. It is calculated by measuring the Dry Bulb Temperature (ambient air temp), Wet Bulb Temperature (humidity/evaporation), Globe Temperature (radiant heat), and Wind Speed in metres per second.

Leighton’s safety managers and supervisors are provided with the required training and instruments to calculate TWL, and monitor it on and hourly basis. TWL readings are used to categorise predefined working zones, each with corresponding control measures. These are broken down as follows:

Working Zone

Control Measures

Unrestricted Zone
(TWL <220)
  • No specific precautions apply
Acclimatisation Zone
(TWL 140-220)
  • No added precautions for acclimatised workers
  • Unacclimatised workers must follow Buffer Zone recommendations
  • Cooled, bottled hydration must be readily available
Buffer Zone 
(TWL 115-140)
  • Cooled, bottled hydration must be readily available
  • Shaded area for work breaks must be available
  • People must not work alone
  • No unacclimatised worker
  • Fluid intake of 1L+ per hour required
  • Work-rest cycle: 40mins work – 20 mins rest
  • Self pacing of work is permitted
Withdrawal Zone
(TWL >115)
Same as Buffer Zone but with the following additional measures

  • Work-rest cycle: 20mins work – 40 mins rest
  • Cooling Vests and Neck Ties to be worn if practical
  • Heart rate monitors to be worn
  • Forehead thermometers to be worn
  • For durations greater than 60 mins the work and controls must be approved by the accountable
    construction manager and a senior H&S Coodinator.


Education & Training

Studies have shown that workers who are educated on hydration and fluid intake recommendations are far less likely to become dehydrated or suffer from heat related conditions both at home and in the workplace.

Leighton Contractors provide a comprehensive hydration training program which involves:

  • raising heat stress awareness,
  • educating workers on appropriate measures to take before, during and after their shifts in order to avoid heat
  • recommended fluid intake guidelines,
  • technical training for supervisors and safety professionals on how to measure, calculate and monitor TWL, and
    how to effectively implement controls
  • toolbox talks
  • hydration testing – urine specific gravity, heart rates, body temperatures and weight loss
  • guidelines for rehydration
  • meal break scheduling
  • recording data

Electrolyte Replacement

When workers sweat they don’t just lose water but also essential salts and minerals known as electrolytes. In order to stay hydrated and maintain optimal performance, it is vital that workers replenish lost electrolytes along with water. As such, electrolyte drinks play an integral role in any successful workplace hydration program.

Leighton Contractors at the Australia Pacific LNG Project choose THORZT Electrolyte Drink as their recommended electrolyte replacement beverage. THORZT is provided on site alongside water, as part of their comprehensive hydration program.

THORZT contains electrolytes (potassium, calcium, sodium, chloride, & magnesium), branch chain amino acids (isoleucine, leucine & valine), and low GI carbohydrates for sustained release of energy throughout the day – without the sugar spike. THORZT is caffeine and gluten free, and is also available in sugar free.
THORZT’s 5 great tasting flavours encourage fluid consumption among Leighton workers, keeping them hydrated and performing at their peak throughout the workday.

Positive Outcome

The Australia Pacific LNG project is ongoing and due for completion in the 2nd quarter of 2014. To date the project has successfully achieved is goal of ‘zero heat stress related incidents’.

Interested in implementing a Heat Stress Management Program on your site? No idea where to begin? Contact THORZT
today for a free hydration consultation.



The Australian Mine Safety Journal, January Edition, “Feeling the Heat”

To learn more about managing heat stress in the workplace, download our FREE Heat Stress White Paper.

Receive Exclusive Content and Promos

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Recommended Blogs


It only takes 1% of dehydration to result in lowered productivity! Most of us think of dehydration as a summer problem. The days are longer