Issue link: https://hi.iaq.net/i/650541
IAQA 18th Annual Meeting & Indoor Environment and Energy Expo (IE3) The views and opinions herein are those of the volunteer authors and may not reflect the views and opinions of IAQA. The information is offered in good faith and believed to be reliable but it is provided without warranty, expressed or implied, as to the merchantability, fitness for a particular purpose or any other matter. manner that allows for proper closure and shall comply with applicable UL, SMACNA and NFPA standards, as well as local, regional, state and federal codes. E. Using Engineering Controls to Prevent Cross-Contamination In accordance with ACR, the NADCA Standard, engineering controls shall be used to ensure worker safety and health, and to prevent cross-contamination. Engineering controls may include, but are not limited to source control, isolation barriers, pressure differentials, dust suppression methods, HEPA vacuuming and filtration, detailed cleaning, temperature and humidity control, and a sanitary approach. Proper containment is critical for any HVAC Cleaning project to ensure that debris is not allowed outside the HVAC system during the cleaning process. It is of utmost importance that containment is used.ACR specifies three levels of containment. Level 1 Containment (the minimum level of containment that shall be used on all HVAC system cleaning projects) involves the following: Negative pressure Protective coverings Cleaning equipment & tools maintenance Cross – contamination control F. Other General Cleaning Requirements & Recommendations • Schedule HVAC system cleaning during periods when the building is unoccupied (if possible). • Ensure the use of negative air pressure. • Be sure to protect the ductwork during cleaning by choosing appropriate tools & methods. • Utilize well-controlled brushing or air washing of duct surfaces. • Utilize HEPA filtered vacuuming equipment if it is exhausting indoors. • If using biocides, be sure to select only those products registered by the EPA for such use. (See NADCA's White Paper on Chemical Applications) • Coil & drain pan cleaning can help reduce microbiological pollutants in the system. • Porous materials that are contaminated or water-damaged should be removed and replaced. • After proper cleaning & restoration, utilize a preventative maintenance program to prevent recurrence of problems in the HVAC system. Proper Cleaning Procedures Cleaning work should follow the pathway of the HVAC system's designed airflow, beginning at the system's return air intakes. Cleaning should then proceed from return air intakes to the air handling unit, and then out through the supply trunk line, branch runs and discharge points. This work sequence, when properly performed, is designed to reduce the likelihood of cleaned portions of the ventilation system becoming re-contaminated. ACR, The NADCA Standard provides guidance for proper cleaning of HVAC system components. For example, it is recommended that air-handling coils, fans, condensate pans, drains and similar non-porous surfaces be wet cleaned in conjunction with mechanical methods. Efforts to control water extraction shall be sufficient to collect debris and prevent water damage to the HVAC components and surrounding equipment and structure. The capture, containment, testing and disposal of waste water generated while performing wet cleaning shall be in accordance with applicable local, regional, state and federal regulations. According to ACR,air ducts shall be cleaned to remove all non-adhered substances and shall be capable of passing NADCA cleanliness verification tests. Air ducts shall be accessed through service openings in the