The question it answers
IREQ, required clothing insulation, estimates the insulation a clothing ensemble needs under specified cold and activity conditions. It forms part of assessing cold at work. It does not assign a universal safe temperature to a garment or replace assessment of local cooling of the hands, feet or face.
Input data
Assessment combines environmental conditions, metabolic activity and clothing insulation. Air temperature alone is insufficient. Wind, radiation and exertion alter heat exchange. Inputs must represent the actual task and its variation during the shift, rather than using a moment of maximum activity to represent the whole working period.
Comparing required and available insulation
Calculated insulation is compared with that provided by the ensemble actually worn, applying the method’s corrections. If protection is insufficient, exposure may need limiting and recovery periods arranging, alongside improved conditions. Interpret results within the model’s limits and individual characteristics, without turning an estimate into a guarantee that harm cannot occur.
Changes between activity and waiting
In a hypothetical example, someone loads products in a cold room, then remains still checking labels. During waiting they generate less heat, despite wearing the same clothes. Assessing loading alone may underestimate the second period’s needs. Describe both scenarios and organise work to prevent protection adequate during exertion becoming insufficient afterwards.
What IREQ cannot resolve alone
Acceptable overall insulation does not exclude cooling of extremities, contact with cold surfaces or breathing difficulties under certain conditions. Clothing moisture, fit, mobility and compatibility with other equipment also matter. Adding layers without considering these factors may hinder the task without resolving the exposure causing the problem.
Professional application
The cited INSST technical note explains the method and its application conditions as technical guidance. Calculation requires reliable data and personnel familiar with its assumptions. Review assessment when the task, environment or clothing changes. Exposed workers’ experience helps identify situations inadequately represented by the calculated scenario.
