Air quality Webcast: Your questions answered
At the recent Plant Engineering Webcast, "Keep your cool while keeping your facilities cool," there were a number of questions that could not be answered during the allotted time. Jim Magallanes, president of TechniCool Innovations Inc. and the presenter at the Webcast, answered a number of audience questions here. To view the on-demand version of the Webcast, click here:
Q: What are OSHA’s Indoor Air Quality requirements for air temperature?
Magallanes: OSHA does not specifically give a temperature that you need to keep your plant under. However when the temperature goes above 95 degrees, they recommend the following to prevent any kind of heat related illness or injury:
1. Increase the employees’ water intake
2. Increase the frequency and duration of breaks
3. Limit exposure of heat
Q: Please discuss:
1) Personnel work area cooling in large, open situation.
2) The most economical method to cool bulk powder materials (large capacity on-line).
Magallanes: 1) I would recommend cooling personnel work areas using small portable air conditioners in a larger warehouse space. Portable air conditioners provide the best way to keep your employees cool during the hot summer months.
2) I would recommend using a large ducted spot cooler to keep bulk powder materials cool. The mobile air conditioner provides cool dry air to keep the bulk powder material cool. A fan will help your employees keep cool by helping them perspire and regulate their body temperatures, but will not lower the temperature to keep the bulk powder cooler. An evaporative cooler will lower the temperature of the air, but will also add moisture to the air. The bulk power will absorb the moisture in the air, and may contaminate the powder.
Q: The portable units appear to have the heat exhaust close to the desired environment to cool. Are there any options like tubing to transport heat further from the unit to reduce air mixture and improve operating efficiency by keeping the input flow cooler? How about portable wall that might control air flow?
Magallanes: There is ducting that can be used to duct the cold air to the area that needs to be cooled. On the smaller 1-ton air conditioners the cold air can be ducted up to 40 feet and the larger 2-ton air conditioners can be ducted up to 60 feet. By ducting the cold air to the areas, the warm exhaust air will not to be ducted away.
Q: Any rules of thumb for airflow in a plant for employees and machinery?
Magallanes: There is no rule of thumb for airflow or cooling in a plant for employees or machinery. Inside a building the rule of thumb is 1-ton of cooling for every 400 sq. ft. However the goal of spot cooling in a warehouse is to blow the cold air directly onto the employee or machine. Portable spot coolers have a temperature drop between 15-25 F, depending on the humidity in the air. This will give you an idea of the temperature of the cold air that will be blown onto the employee or machine.
Q: What is the maximum CFM offered by ducted cooling, either air- or water-cooled?
Magallanes: The airflow of the portable air conditioner is dependent on the size of the air conditioner. The industrial portable air conditioners that can be ducted produce the following amounts of airflow volume:
- 10,000 Btu/hr: 265 CFM
- 13,200 Btu/hr: 440/380 CFM (High/Low)
- 18,000 Btu/hr: 530 CFM
- 24,000 Btu/hr: 708/600 CFM (High/Low)
- 39,000 Btu/hr: 1060 CFM
- 60,000 Btu/hr: 1580 CFM
Q: Are these unit clean room approved?
Magallanes: I don’t know of any commercial portable air conditioners that have a clean room rating. The units come with standard foam filters that can be washed and clean. If you wanted to use these portable air conditioners in a clean room environment, and have a better filtering process on them I am sure you could use them in conjunction with a high efficiency HEPA filter. However you would need to use an inline fan to boost the airflow up to it’s original specification, because a HEPA filter would severely decrease the airflow volume.