Indicators to assess physiological heat strain - Part 2: Delphi exercise

Area of Science:

• Occupational Health
• Environmental Physiology
• Workplace Safety

Background:

• Heat stress poses significant risks to workers globally.
• Existing thermal stress indicators (TSIs) vary in their effectiveness and applicability.
• A standardized approach to selecting TSIs is needed to ensure worker protection.

Purpose of the Study:

• To identify and validate criteria for adopting thermal stress indicators (TSIs).
• To determine the relative importance of these criteria through expert consensus.
• To establish a framework for comparing and developing TSIs for heat-exposed workers.

Main Methods:

• A Delphi exercise involving 20 occupational health and safety experts was conducted.
• Two iterations of the Delphi exercise were used to reach consensus.
• Expert opinions were used to weigh 17 identified criteria for TSI selection.

Main Results:

• Consensus was reached on 17 criteria for selecting TSIs, with high reliability (Cronbach's α = 0.86).
• Criteria were weighted across three pillars: occupational health (55%), physiological strain mitigation (35.5%), and cost-effectiveness (9.5%).
• Three criteria—correlation with core temperature, heat stress categorization, and provision of safety recommendations—were deemed most critical.

Conclusions:

• The 17 validated criteria provide a robust framework for selecting and comparing TSIs.
• This framework supports the development of more effective TSIs for protecting workers from heat stress.
• The criteria balance physiological, practical, and cost considerations for workplace heat safety.