Effect of the Evaporative Cooling on the Human Thermal Comfort and Heat Stress in a Greenhouse under Arid Conditions

Table 1

Various types of greenhouse work and the corresponding highest permissible WBGT values.

Type of greenhouse work	𝑀 (met)	Permissible WBGT (°C)
No work is recommended	—	>32.5
Preparation of spinach, defoliation of strawberry, leaves swing, standing relaxed, and so forth	0.7–1	<32.5
Disbudding, training, pinching, planting, chemical spraying, and so forth	1-2	<30.5
Weeding, fruit thinning, fertilizing, standing poles, extending screens, and so forth	2-3	<29.0
Mowing, preparation of nursery beds, and so forth	3-4	<27.5
Soil mounding, row creation, removal of crop wastes, and so forth	4-5	<26.5
Digging with a spade, working with an axe, and so forth	5–7	<25