Thermal radiation from an ammonia flare is minimal since ammonia only has nitrogen and hydrogen.
Combustion produces nitrogen and water vapor.
Nitrogen is a very poor radiator of heat and water vapor is a weak radiator. The radiation levels should be calculated and checked for operator safety concerns only. Typically, the flare is mounted on top of the access stair support column along the side of the low pressure refrigerated storage tank. Operation of the flare only occurs in the event of refrigeration failure or power failure. Since refrigeration failure is very unlikely, the prime cause of a flare event is a long term power failure.