Wet bulb globe temperature (WBGT)

Worked example

Outdoors, tnwb 78°F, tg 100°F, ta 88°F.

0.7 × 78 + 0.2 × 100 + 0.1 × 88 = 83.4°F

The same readings indoors (no ta term): 0.7 × 78 + 0.3 × 100 = 84.6°F.

Where it appears on the exam

• ASP: ASP11 Domain 1, Mathematical Calculations

  Blueprint: ASP11 Domain 1, task 6: climate and environmental conditions

  Practice: Heat Index, WBGT and Wind Chill Calculations

• CSP: CSP11 Domain 6, Occupational Health and Applied Science

  Blueprint: CSP11 Domain 6, task 1: occupational exposures (heat/cold)

  Practice: Applied Science: Radiation, Ventilation, Heat and Force

• CHST: CHST5 Domain 1, Hazard and Risk Identification and Control

  Blueprint: CHST5 Domain 1, knowledge 22: working in extreme climates

  Practice: Heat Index, WBGT and Wind Chill

Source

Questions

What is the formula for wet bulb globe temperature (WBGT)?

Outdoors: WBGT = 0.7 tnwb + 0.2 tg + 0.1 ta; Indoors: WBGT = 0.7 tnwb + 0.3 tg. tnwb = natural wet bulb; tg = globe; ta = dry bulb (air) temperature, all in the same units.

Will this formula be given on the BCSP exam?

BCSP says the formula is included in the question whenever one is needed, unless the question is testing whether you know the formula. You can't bring a formula sheet into the exam, so learn what each formula does and when to use it.