The OSHA guidelines are designed for employees in the workplace. OSHA recommends a workplace temperature control in the range of 68-76° F and humidity control in the range of 20%-60% as specified in OSHA Manual. The Complete OSHA Technical Manual includes Noise Measurement and Guidelines as well. The EEC has also set guidelines, which are lower than the US standards.
See https://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_2.html#5. The Complete Technical Manual can be read at https://www.osha.gov/dts/osta/otm/otm_toc.html, which also includes Noise Measurement and Guidelines as well at https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=standards&p_id=9735.
"Appropriate temperature, humidity and air circulation levels should be maintained in the fitness floor area. The following levels are recommended: Temperature: 68 to 72 degrees Fahrenheit."
- ACSM's Health/Fitness Facility Standards and Guidelines. 2nd Ed.
The temperature should be what is comfortable for your clients. It will be different for each of your classes. I suggest that the issue be resolved at the management level since they will be responsible for the overheated client in a room that is set too warm for regular aerobics classes. We consider 70 degrees too high for regular aerobic classes. It would probably be fine for the over 60 demographic. For an aerobics class, a room temperature of no higher than 68 degrees and 50% humidity is recommended. Remember, just because your clients are sweating does not mean that they are getting a good workout. In an overheated environment, they could simply be overtaxing their cardiovascular system, which can lead to dangerous physiological conditions.
Both OSHA and The American College of Sports Medicine have recommendations. IFA has developed the following along those guidelines: The aerobics, cardio, weight training and Pilates areas should be at about 65 to 68 degrees. Yoga areas should be somewhat warmer at no higher than 80 degrees. Pool areas should be in the 70 to 80 range. Humidity levels for all areas should be around 40% to 60%.
It varies all over. What is loud to one group is inspiring to others. In any case, music should not be louder than the standards set by the EPA. We are currently updating our material to include environmental guidelines. Gyms and classes including instructor who do not adhere to these guidelines leave themselves open to legal ramifications in the future as well as workmen's compensation considerations as this subject becomes more widely understood.
At 85 db the EPA standard for safe sound is 45 minutes. At 88 db the EPA standard for safe sound is 23 minutes. EPA regards 91 db as unsafe for any length of time over 11 minutes. The European Union has set the maximum legal limit for recreational sound in its member countries as 85 dB with a suggested level of 80 dB.
These are the noise guidelines set by the EPA for db/duration.
dB Noise Level EPA Noise Exposure Limit
70 dB 24 hours
79 dB 3 hours
82 dB 90 minutes
97 dB 3 minutes
102 dB 53 seconds
107 dB 16.7 seconds
117 dB 1.7 seconds