Commission the System
Title 24 Requirement
Install ventilation equipment to deliver the amount of whole-building ventilation calculated in Step 3.
Measure whole-building ventilation airflow to ensure compliance. The airflow of the whole-building ventilation system must be tested after installation with a flow hood or other flow measurement device to verify that it provides at least the required minimum airflow calculated in Step 3.
ASHRAE 62.2-2007 & ASHRAE 62.2-2010
Information on the ventilation design and installation, instructions on proper operation, and instructions detailing any required maintenance must be provided to the building owner and occupant.
Best Practice Recommendation
ASHRAE Standard 62.2 DOES NOT require that you verify the airflows of the kitchen range hood and bath fans, but if you have flow testing equipment, this is a quick and easy way to find installation problems, such as a stuck backdraft damper, a wall cap painted shut, or a squashed duct in the attic. Here are the air flows that your prescriptively sized local exhaust equipment should deliver:
- Kitchen Range Hood
- 100 cfm or more airflow at low speed if operated intermittently with a sound rating of no more than 3.0 sones at low speed
- — OR —
- 5 air changes per hour if operated continuously.
- Bathroom Fan
- 50 cfm airflow @ 0.25 in. w.c. if operated intermittently
- — OR —
- 20 cfm if operated continuously.
Check All Parts of the Ventilation System
- Check to make sure ventilation design has been followed. Look out for field substitutions that might diminish quality and effectiveness.
- Make sure all the fans and their controls operate as designed.
- Check all accessible ductwork, especially in the attic where it is easy for someone to crush a duct or knock it off the fan or fitting.
- Ensure that all backdraft dampers are free to operate in fans, fresh air inlets, and exhaust outlets. A misplaced screw in ductwork can obstruct free movement of a backdraft damper.
- Check wall caps, which sometimes are painted shut when the building's exterior is sprayed.
Perform a Final Safety Test if Combustion Appliances are Present
As in the initial assessment of combustion safety in Step 1, choose the test method that will meet your needs:
- Follow the BPI guidelines for combustion safety testing used during the initial assessment of the home.
- Use the prescriptive standard in the ASHRAE Standard 62.2 to avoid backdrafting. When naturally-vented appliances are present, the combined exhaust of the two largest fans in the house cannot exceed the equivalent of 15 cfm per 100 sq ft of living area (0.15 cfm per sq ft). For example, since the dryer and the range hood are normally the largest fans, their combined airflow at the highest setting cannot exceed 15 cfm/100 sq ft of living area. So in a 2,000 sq ft house, the two largest fans operating on highest speeds must not exceed 300 cfm of airflow (0.15 cfm x 2,000 sq ft = 300 cfm).
Set Programmable Controls, If Used
If the whole-building ventilation system is designed to operate intermittently, a programmable control is required. Set the programmable timer and verify that it is set to provide the required ventilation run time at the airflow required to supply equivalent ventilation to the continuous airflow calculated in Step 3. Remember, when the whole-building ventilation system runs for less time, the airflow of the system must be increased significantly to provide equivalent ventilation. The less time per day the system operates, the higher the airflow must be to compensate.
Teach Occupants How to Use Their Ventilation Equipment
The ventilation requirements of ASHRAE Standard 62.2 are met by providing fans and controls that ensure that whole-building ventilation will occur at the recommended levels. But unless occupants know how and why to use the ventilation equipment, the designed system is unlikely to do much to improve indoor air quality.
For over 30 years, contractors and program managers have complained that homeowners and renters don't operate or maintain HVAC equipment properly. And in the occupants' defense, most toasters come with more information on operation than the HVAC equipment in a home or apartment. So it's not surprising that equipment is often misunderstood and neglected.
So how can the system for passing along information about ventilation equipment be improved? Think of yourself as a ventilation teacher during the final walk-through of your project. Your goals are to engage your "student" in as many ways as possible. Good teachers know that lecturing is not as effective as having students participate in a lesson, so here are some ventilation teaching tools to use during your short walk-through:
- A simple, leave-behind ventilation brochure that describes the reasons to use the installed ventilation equipment, ways to control pollutant sources, signs of indoor air quality problems, and when to operate the installed ventilation equipment. The brochure can be used as an outline of your ventilation spiel. The illustrations in the brochure are the same as the illustrations used for labeling the ventilation equipment.
- Sample labels for local exhaust and whole-building ventilation equipment that can be printed on adhesive stock from an office supply store. Labels are provided that remind occupants to turn on the range hood when cooking, turn on the bath fan when bathing, and turn on the nearest fan when they smell an odor. Because whole-building ventilation systems have so many different options, each contractor needs to develop a label that describes the home’s whole-building ventilation system, with brief operation and maintenance information.
- Ventilation icons that can be downloaded to create labels or other custom materials.
Sample Plan for Using the Ventilation Teaching Tools
Before the Walk-Through
- Print copies of the ventilation brochure for occupants. Probably the most cost-effective printing method is to download the file to a flash drive and take it to an office supply store for two-sided photocopying. Space is provided on the brochure to add your business name and contact information.
- Print copies of ventilation labels for local exhaust equipment on adhesive label stock. The sample labels for local exhaust equipment are set up to be printed on 2”x2” adhesive labels available at an office supply store or online. (Each label manufacturer provides online templates that allow users to paste in text and illustrations.) Removable labels are available to make eventual removal easier. Again, it may be most cost effective to download the labels in the appropriate template to a flash drive and have an office supply store laser-print the labels. Since the labels will be used around the stove and in the bathroom, laser printing will be more durable than ink jet printing.
- Develop a whole-building ventilation system label that fits your project.
- Practice going over the major points of the ventilation brochure until you can do it smoothly in a short amount of time.
- If possible, prepare estimated electrical costs for the whole-building ventilation system so you can help people have a realistic idea of what it will cost to use their ventilation system as designed.
During the Walk-Through
- Give the occupant a copy of the ventilation brochure to use during your walk-through. Use the bold headlines as the outline of a ventilation mini-lesson that covers:
- why ventilation fans are needed
- where indoor pollutants come from
- ways to reduce pollutant sources
- signs of indoor air quality problems
- the location and operation of the whole-building ventilation equipment
- when to use local exhaust fans
- Show the occupant where the whole-building ventilation system is located. Put the adhesive label you created for the system on or near the equipment. Explain what the equipment does, how to operate it, and how to maintain it. Explain programmable controls, if used.
- Show the occupant how to operate the kitchen range hood and have him or her operate the controls. Put cooking and odor labels in the range hood and remind occupants to use the range hood whenever cooking and when an odor is noticed. Describe how to clean the filter(s).
- Move to the bathroom and demonstrate the bath fan controls. Have the occupant operate the controls. Put bathing and odor labels on the controls or the bathroom mirror and remind occupants to use the bath fan when bathing and when an odor is noticed. Describe any maintenance required.