When does AHRAE Standard 15-2013 require that each machinery room activate an alarm and mechanical ventilation?
a. When the TLV-TWA (Threshold Limit Value-Time Weighted Average) is exceeded.
b. When the UTL (Upper Threshold Limit) is exceeded.
c. When the COP (Coefficient of Performance) drops 5% of the original value.
d. When the EEL (Emergency Exposure Limit) is exceeded by 10%.