This checklist is designed to help the commercial/industrial community understand NADCA’s recommendations regarding the HVAC system cleaning process. NADCA advises reviewing the checklist items below BEFORE hiring an air duct cleaning company.
NADCA sets the industry standard for HVAC system cleaning and when done correctly, HVAC cleaning can be very beneficial for our facility. NADCA’s dedication to quality promotes a higher standard of performance for all of its members—which can help give customers peace of mind.
IN ORDER TO BECOME A NADCA MEMBER, A COMPANY MUST:
In addition, all ASCS certified individuals must acquire continuing education credits to maintain certification.
Questions/Discussion Topics for Commercial/Industrial HVAC System Cleaning Projects
1.0 Overview: Inspections are an important component of any HVAC cleaning and restoration project. HVAC inspections shall be performed to determine the need for cleaning. HVAC inspections shall also be performed to determine the scope of work, engineering controls, safety measures and tools and equipment necessary to perform a cleaning and restoration project.
1.1 When to Perform an Inspection: Inspections shall be performed before and after HVAC cleaning and restoration projects. It is also recommended that routine inspections be performed as part of a proactive energy and indoor air quality management plan.
1.2 HVAC Inspector Qualification: It is recommended that a qualified HVAC inspector, such as an Air Systems Cleaning Specialist (ASCS), Certified Ventilation Inspector (CVI), or equivalent, be used to determine the preliminary state of HVAC system cleanliness. At minimum, such personnel shall have a verifiable working knowledge of basic HVAC system design, fundamental HVAC engineering practices, current industry HVAC cleaning and restoration techniques, and applicable industry standards. Individuals who are inspecting for microbial contamination shall be qualified (through training and experience) and licensed (where applicable by law) to determine Conditions 1, 2 and 3.
1.2.1 Risk Assessment: Prior to conducting an inspection of the HVAC system the inspector shall have a clear understanding what impact the inspection process may have on the building environment and its occupants.
1.3 HVAC Pre-Inspection: HVAC plans, building plans, and understanding the layout of the home or building will provide important information needed to establish the scope of work. Both building floor plans and mechanical plans, if available, shall be used during the inspection, cleaning and restoration work.
1.4 Appropriate Environmental Engineering Controls: HVAC inspection activities may adversely influence a building's indoor environment. Of primary concern is the disturbance of settled particulate and the potential for disturbed particles to be released into occupied areas. During an inspection, appropriate engineering controls shall be used to manage the general workspace environment.
1.5 Routine HVAC Inspection: It is recommended that HVAC system inspections be part of a building's overall energy and indoor air quality management plan, and that the inspections be addressed in accordance with documents such as ANSI/ASHRAE/ACCA Standard 180 Standard Practice for Inspection and Maintenance of Commercial Building HVAC Systems and NFPA 90-A Standard for the Installation of Air-Conditioning and Ventilating Systems Today.
1.5.1 Inspection Schedule Table
HVAC systems shall be routinely inspected for cleanliness by visual means. Table 1 provides a recommended inspection schedule for major HVAC components within different building use classifications. The inspection intervals specified in Table 1 are minimum recommendations
220.127.116.11 It is recommended that more frequent cleanliness inspections be performed when geographical, human or mechanical conditions make it necessary.
HVAC Cleanliness Inspection Schedule (Recommended Intervals)
|Building Use Classification||Air-handling Unit||Supply Duct||Return Duct / Exhaust Duct|
|Residential||1 year||2 years||2 years|
|Commercial||1 year||1 year||1 year|
|Industrial||1 year||1 year||1 year|
|Healthcare||1 year||1 year||1 year|
|Marine||1 year||2 years||2 years|
1.6 HVAC System Inspection – Construction, Retrofit and Remodel: HVAC system components often collect significant amounts of debris and particulate during construction activities within a building. It is recommended that new and existing HVAC systems that are part of a construction, retrofit or remodel project be inspected and verified as clean before the system is permitted to operate.
1.7 Performing HVAC System Component Inspections: The cleanliness inspection shall include, at minimum, 10% of the HVAC system components. If the inspection is being conducted as part of a mold remediation project in accordance with IICRC Standard S520, then all components of the HVAC system shall be inspected.
1.7.1 Air-Handling Unit Inspections: The air-handling unit (AHU) cleanliness inspection shall include components within the unit, including filters and air bypass, heating and cooling coils, condensate pans, condensate drain lines, humidification systems, acoustic insulation, fans and fan compartments, dampers, door gaskets and general unit integrity. This would also include components such as fan coil units, evaporative coolers, etc.
1.7.2 Supply Air Duct Inspections: The supply duct cleanliness inspection shall include supply components including, but not limited to, air ducts, controls, mixing/control boxes, reheat coils and other internal components.
1.7.3 Return Air Duct Inspections: The return air duct cleanliness inspection shall include return components including, but not limited to, return air ducts, dampers, return plenums and grilles.
1.7.4 Exhaust Air Duct Inspections: General exhaust, bathroom exhaust and heat recovery exhaust are considered part of the ventilation system and a part of the overall inspection.
1.7.5 Internal Components: Internal components that are in the HVAC system air stream such as coils, dampers, fans, etc., shall be inspected for cleanliness during the AHU or air duct inspection.
1.7.6 Damaged Components: Damaged components observed during the inspection shall be documented.
1.8 Exposure to Hazardous Materials: If the possibility exists that the inspector or others may be exposed to hazardous materials, consultation with a qualified indoor environmental professional (IEP) or other health and safety professional is recommended.
1.9 Inspecting for Mold Contamination: It is recommended that the HVAC system cleanliness inspection include a preliminary determination of the level of suspect mold contamination (Condition 1, 2 or 3) and other biological activity. In the event suspect mold growth or other biological activity is identified, it is recommended that the cause and extent be further assessed, if necessary, by an indoor environmental professional (IEP) or other appropriate professional, or as required by Authorities Having Jurisdiction (AHJ).
1.9.1 If the inspection of an HVAC unit's air-handling components reveals suspect mold contamination, then the supply and return ducts shall be inspected during that same inspection time rather than in accordance with the intervals specified in Table 1.
1.9.2 If water damage or suspect mold growth is observed on building products or furnishings, this condition is not within the scope of this document.Refer to IICRC S520 and/or Authorities Having Jurisdiction.
1.10 System Assessment: Information collected from the HVAC inspection shall be documented and evaluated to assess the condition of the HVAC system at the time of the inspection. The assessment shall include a recommendation on the need for cleaning, a clearly defined scope of work for the cleaning and restoration project, recommended cleaning techniques, a determination of the environmental engineering controls required for the workspace, and any unique requirements.
2.0 Overview: A written work plan is a document that communicates responsibilities and specific tasks associated with the cleaning and restoration project. The work plan is created using information gathered from the HVAC inspection and system assessment.
2.1 Purpose: The primary purpose for providing a written work plan is to allow the client, the cleaning contractor, field personnel and others involved in the project to have a clear understanding of what work tasks and procedures will be performed.
2.2 Scope of Work: A scope of work shall be included that clearly identifies which HVAC components are to be cleaned or restored, as well as those components NOT included in the process. The scope of work shall also include the environmental engineering controls required for the workspace, and any unique requirements.
2.3 Means and Methods: It is recommended that the written work plan identify the specific means and methods of cleaning and restoration that will be used for the particular project.
2.4 Other Trades and Their Tasks: When applicable, it is recommended that the work plan include the name of all firms, contractors and representatives involved in the project, along with contact information. It is recommended that the tasks others will perform be clearly identified.
2.5 Project Schedule: When appropriate, it is recommended that the work plan include the dates and times the work will take place and an overall timeframe for completion.
2.6 Work Site Communication Plan: When more than one company is associated with the project, it is recommended that the written work plan list the name, company name and contact information of pertinent individuals, along with their responsibilities to the project.
2.7 Product Submittals: All general use and/or specific "chemical type" products and coatings specific to the project shall be clearly listed on the work plan. Additionally, the manufacturer's instructions for use and application shall be available at all times for workers and others.
2.7.1 Material Safety Data Sheets (Includes MSDS and SDS): The work plan shall include Material Safety Data Sheets for all chemical products to be used on the project. In addition, the MSDS shall be maintained on-site and available for review for the duration of the project. Documentation showing that the products have been submitted to the owner for review can also be included in the work plan.
2.7.2 Controlling Vapors and Odors: Where applicable, the plan shall include a description of Engineering Controls (see Section 3) to be employed to control occupant and worker exposure to chemical vapors and odors.
2.8 Safety Plan & Safety Concerns: When life safety detection equipment (e.g., air duct sensors and smoke detectors) needs to be off-line or disabled, the work plan shall address life safety concerns, which will likely require the input of others. It is recommended that the written work plan define the responsibilities of each organization's designated representative involved with executing the plan for the duration of the HVAC system cleaning and restoration project.
2.9 Disclaimers: It is recommended that the work plan include disclaimers to clearly identify items that are not covered under any warranty or guarantee.
3.0 Overview: Engineering controls shall be used to ensure worker safety and health, and to prevent crosscontamination. 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.
3.1 Equipment Maintenance: All contractor equipment shall be maintained in good working order, consistent with applicable jurisdictional requirements, including but not limited to vacuum collection equipment, power tools, pressurized air sources, electrical power cords and plugs, ground fault protection devices, vacuum collection hoses, fluid and pneumatic lines, manual and mechanical rotary brush systems, pneumatic cleaning systems, air duct zoning devices, ladders, staging equipment, and hand tools.
3.1.1 Equipment Maintenance Before Project: Before any equipment is brought onto the work site it shall be cleaned and inspected to ensure that it will not introduce contaminants into the indoor environment or HVAC system.
3.1.2 Equipment Maintenance During a Project: During a project all equipment shall be serviced as needed to limit possible cross-contamination from poor hygiene, and/or unsafe operating conditions for service personnel and building occupants.
18.104.22.168 Collector Filter Maintenance During a Project: Any activity requiring the opening of contaminated vacuum collection equipment on-site, such as servicing or filter maintenance shall be performed in an appropriate containment area or outside of the building.
3.1.3 Transportation and Relocation of Equipment: All collection devices, vacuums and other tools and devices shall be cleaned or sealed before relocating to different areas of the building and before removing the equipment from building.
3.1.4 On-Site Equipment Verification: It is recommended that an on-site maintenance verification be performed on vacuum collection equipment prior to commencement of work.
3.2 Fuel-powered Equipment: Generators, vacuum trucks, air compressors or other fuel-powered equipment shall be positioned in a location to prevent combustion emissions and air exhaust emissions from entering an occupied space.
3.2.1 Location shall be monitored and managed during a project to prevent the introduction of combustion emissions into the occupied space.
3.3 Vacuum Equipment Exhausting Indoors: When using vacuum collection equipment exhausting within the building envelope, it shall utilize HEPA filtration with 99.97% collection efficiency at 0.3 micron particle size. This requirement applies to all cleaning projects.
3.4 Negative Pressure Requirements: A continuous negative pressure shall be maintained in the portion of the HVAC system being cleaned in relation to the surrounding indoor spaces. The negative pressure shall be verified at representative locations during the cleaning process.
3.5 Handling of Contaminated Materials: To prevent cross-contamination, all contaminated materials removed from the HVAC system shall be properly contained prior to removal from the building.
3.5.1 Materials deemed to be hazardous by governmental agencies shall be handled in strict accordance with any applicable local, regional or national codes.
3.6 Ambient Air Cleaning: It is recommended that ambient air cleaning using HEPA-filtered air scrubbers be employed as a supplemental engineering control for particle reduction, during and immediately after HVAC cleaning and restoration work. It is recommended that ambient air cleaning provide a minimum of four (4) air changes per hour.
3.7 Control of Product Emissions: Any application of cleaning agents or other chemicals shall be used in strict accordance with manufacturer's recommended procedures and product application instructions, including exhaust ventilation as required.
3.8 Negative Pressure Failure: To prevent negative pressure failure due to equipment malfunction or electrical power interruption, it is recommended that backup equipment be on-site with a dedicated power supply properly designed to carry the intended current draw being utilized.
3.9 Level 1 Containment: Level 1 is the minimum level of containment that shall be used on all HVAC system cleaning projects.
3.9.1 Negative Pressure: The HVAC system, or area being cleaned/restored, shall be placed under negative pressure during all cleaning activities. Negative pressure shall be sufficient to prevent migration of any particulate material out of the HVAC system.
3.9.2 Protective Coverings: Clean, protective coverings shall be used within the work area. Protective coverings shall extend beyond the work area to provide protection of flooring, equipment, and furniture whenever necessary.
3.9.3 Cleaning Equipment and Tools: All tools and equipment shall be maintained as described in Section 3.1.
3.9.4 Cross-Contamination Control: Engineering controls shall be in place to control contaminant discharge from the HVAC system and/or cross-contamination into occupied space during the cleaning process.
3.10 Level 2 Containment (Temporary Barriers):
3.10.1 Include Level 1 requirements: All level 1 containment requirements apply to Level 2 Containments
3.10.2 Temporary Containment Barriers: Temporary barriers shall be constructed.
22.214.171.124 It is recommended that containment barriers be erected from floor to ceiling when applicable.
126.96.36.199 It is recommended that above ceiling work areas are isolated from occupied spaces and/or non-work areas when applicable.
188.8.131.52 It is recommended that containment barriers are built utilizing 6-mil fire retardant polyethylene sheeting or equivalent.
184.108.40.206 These barriers are recommended to be sealed airtight where they meet the ceiling, floor, and walls or other areas.
3.10.3 Containment Area Floor: The containment shall have a two-layer floor utilizing 6-mil fire retardant polyethylene or equivalent. The floor material shall extend at least 6 inches (15.2 centimeters) up the containment side walls. The floor material shall be sealed to side walls in a manner that will remain secure and airtight during the depressurization.
3.10.4 Containment Area Access: A zippertype access, with a single flap covering the zipper is the most common work practice.
220.127.116.11 In the event a zipper is not available or practical, then a vertical cut in the containment side wall can provide access into the containment area. The vertical cut shall be entirely covered by two flaps, one on each side of the polyethylene.
3.10.5 Negative Pressure: The containment area shall be kept under negative pressure at all times. The negative pressure shall be sufficient to prevent airborne migration of particulate material out of the containment area.
3.10.6 Validate Negative Pressurization: A manometer or airflow measuring/monitoring device shall be used to validate negative pressurization.
3.10.7 Ambient Air Cleaning Ambient air cleaning with HEPA-filtered air scrubbers shall be performed. Ambient air cleaning shall maintain, at minimum, four (4) air changes per hour.
3.10.8 Dismantling: Interior surfaces of the containment enclosure shall be wet-wiped and/or HEPA vacuumed before moving or dismantling the containment enclosure. In the healthcare environment, an appropriate post-remediation verification shall be performed prior to dismantling the containment.
3.11 Level 3 Containment: Level 3 is a containment with a single chamber decontamination unit.
3.11.1 Include Level 1 and Level 2 Requirements: All of the Level 1 and 2 Containment requirements apply to Level 3 Containments. In addition, the following protective actions shall be used under Level 3 Containment strategies.
3.11.2 Decontamination Facility: A single chamber decontamination facility shall be utilized in conjunction with the containment area. The decontamination chamber shall be attached and sealed directly to the containment area. The decontamination chamber shall be separated from the containment area by a zipper access with single flap or the use of two flaps as described in Level 2 Containment.
3.11.3 Monitoring Requirements: Level 3 Containment areas shall be monitored for negative pressure on a continuous basis by using an instrument sensitive enough to detect a loss of negative pressure. Background monitoring for total particulate shall be performed prior to set-up of containment to establish baseline airborne total particulate concentrations. It is recommended that monitoring also be conducted during set-up of containment. Real time monitoring for total particulate shall be conducted on a regular basis during the work to ensure that particulate is not escaping the containment. If airborne particulate levels exceed background levels, work shall cease until airborne particulate levels are reduced to background levels and the cause of the problem is found and corrected.
3.12 Level 4 Containment: A Level 4 Containment is a containment with a two chamber decontamination unit.
3.12.1 Include Level 1, Level 2 and Level 3 Requirements: All of the Level 1, Level 2, and Level 3 Containment requirements apply to Level 4 Containment areas. In addition, the following protective actions shall be used under Level 4 Containment strategies.
3.12.2 Decontamination Facility: A decontamination facility as described for a Level 3 Containment area shall be utilized, except that the decontamination facility shall consist of two chambers. Each chamber shall be constructed according to the requirements described for a Level 3 Containment area.
3.12.3 Monitoring Requirements: Monitoring requirements described for a Level 3 Containment area apply. In addition, the containment shall have a constant recording pressurization monitor with an appropriate alarm.
3.13 Summary of Engineering Controls: Appropriate engineering controls are mandatory on every HVAC cleaning and restoration project. Protecting workers and building occupants and preventing cross-contamination shall be considered a priority on every project. It is recommended that the above listed engineering controls are considered minimum requirements. When a contractor has any questions about project-specific engineering controls, it is recommended that an Indoor Environmental Professional (IEP) be consulted.
4.0 Overview: All cleaning and restoration procedures shall achieve the minimum level of visibly clean or the specified level of cleanliness verification as defined in the contractual documents for components within the project scope of work.
4.1 Negative Duct Pressurization: Prior to and throughout the duration of the cleaning process, the HVAC system and associated air duct shall be kept at an appropriate negative pressure differential relative to the indoor non-work area. This negative pressure differential shall be maintained between the portion of the HVAC duct system being cleaned and surrounding indoor occupant spaces.
4.1.1 Verifying Negative Pressure Differential: Under all circumstances, you shall verify pressurization differential during the project.
4.1.2 Equipment Exhausting Indoors: When utilizing vacuum collection equipment exhausting indoors it shall be HEPA-filtered and be capable of retaining dislodged debris.
4.1.3 Equipment Exhausting Outdoors: All equipment used to create negative duct pressurization that does not have HEPA filtration shall be exhausted outdoors.
4.2 Service Openings: Service openings may be needed to perform assessment, cleaning and restoration (ACR) procedures. Below are the minimum requirements for service openings.
4.2.1 Service openings installed into the system shall not degrade the structural, thermal, or functional integrity of the system.
4.2.2 Service openings shall be created in a manner that allows for proper closure.
4.2.3 Service openings shall not hinder, restrict, or alter the airflow within the air duct.
4.2.4 Service opening construction materials and methods shall be in compliance with industry standards and local codes, using materials acceptable under those standards and codes.
4.2.5 Materials used in the fabrication of duct access doors and permanent panels shall be those classified for flammability and smoke spread if the material is exposed to the internal airstream. These materials are classified as having a flame-spread rating of not over 25 without evidence of continued progressive combustion and a smoke-developed rating of not over 50, as determined by UL 723.
4.2.6 All tapes used in the installation and closure of service openings shall meet the requirements of UL 181A.
4.2.7 All service openings shall comply with applicable UL, SMACNA and NFPA standards, as well as local, regional, and state codes.
4.2.8 Service Panels
18.104.22.168 Service panels used for closing service openings in the HVAC system shall be of an equivalent gauge or heavier so as to not compromise the structural integrity of the duct.
22.214.171.124 Service panels used for closing service openings shall be mechanically fastened (screwed or riveted) at minimum every 4" on center. The panel shall overlap the ductwork surfaces by a minimum of 1" on all sides.
126.96.36.199 It is recommended that service panels used for closing service openings be sealed with gaskets, duct sealants, mastic or tape.
4.2.9 Prefabricated Duct Access Doors: The gauge of the duct access door shall be based on the pressure class of the duct system and shall be installed according to manufacturers specifications.
4.2.10 Fibrous Glass System Service Openings
188.8.131.52 Access and closure of service openings installed in fibrous glass shall be created and closed in such a manner that there are no exposed fibrous glass edges within the system common to the airstream.
184.108.40.206 Any fibrous glass removed during the installation of a service opening shall be repaired or replaced with like material of the same thickness so that there are no breaks or openings that would degrade the R value, service rating or vapor/air barrier characteristics.
4.2.11 Drilled 1" Service Openings: Drilled 1" service openings shall be closed with materials meeting UL 181 for smoke generation and flame spread.
4.2.12 Flexible Duct Systems: Service openings shall not be made in flexible ductwork.
4.3 Cleaning and Restoration of HVAC Systems: HVAC systems shall be cleaned by using a suitable agitation device to dislodge contaminants from the HVAC component surface and then capturing the contaminants with a vacuum collection device.
4.4 Wet Cleaning, Power Washing, and Steam Cleaning: Wet cleaning, power washing, steam cleaning and any other form of wet process cleaning of HVAC system components shall not damage or result in subsequent damage to the components. Cleaning agents or water shall never be applied to electrical, fibrous glass or other porous HVAC system components.
4.5 Vacuum Collection Equipment: Vacuum collection equipment shall be operated continuously during cleaning. The collection equipment shall be used in conjunction with agitation tools and other equipment to convey and collect debris and prevent cross-contamination of dislodged particulate during the mechanical cleaning process.
4.5.1 Capture Velocity: When the vacuum collection device is used to convey air with debris, it shall maintain a sufficient velocity and negative pressure differential in the portion of the mechanical system being cleaned. Table 2 defines recommended velocities for various types of contaminants.
Table of Velocity Requirements for Contaminant Removal
|Nature of Contaminant||Examples||Design Velocity in FPM|
|Very fine light dust||Cotton lint, wood flour, litho powder||2500-3000|
|Dry dusts & powders||Fine rubber dust, Bakelite molding powder dust, jute lint, cotton dust, shavings (light), soap dust, leather shavings||3000-4000|
|Average industrial dust||Grinding dust, buffing lint (dry), wool jute dust, shoe dust, granite dust, silica flour, general material handling, brick cutting, clay dust, foundry (general), limestone dust, packaging and weighing asbestos dust in textile industries||3500-4000|
|Heavy dusts||Sawdust (heavy & wet), metal turnings, foundry tumbling barrels and shake out, sand blast dust, wood blocks, hog waste, brass turnings, cast iron boring dust, lead dust||4000-4500|
4.6 Confined Space Cleaning: When working inside a confined space, health and safety concerns shall be a priority. The duct support system, internal components, configuration and confined space concerns shall be evaluated for safety prior to entry. It is recommended that a Certified Safety Professional be consulted as needed.
4.7 Air-Handling Unit (AHU) Cleaning: It is recommended that air-handling coils, fans, condensate pans, drains and similar non-porous surfaces be wet cleaned in conjunction with mechanical methods.
4.7.1 Efforts to control water extraction shall be sufficient to collect debris and prevent water damage to the HVAC components and surrounding equipment and structure.
4.7.2 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.
4.8 Air Duct Cleaning: Air ducts shall be cleaned to remove all non-adhered substances and shall be capable of passing NADCA cleanliness verification tests.
4.8.1 Air ducts shall be accessed through service openings in the system that are large enough to accommodate mechanical cleaning procedures and allow for cleanliness verification.
4.8.2 Air ducts shall be cleaned using mechanical agitation methods to remove particulate, debris, and surface contamination.
4.8.3 Dislodged substances shall be captured with a vacuum collection device.
4.8.4 Cleaning activities shall not damage any HVAC components.
4.9 Dampers: Dampers and any air-directional mechanical devices shall have their position marked prior to cleaning and shall be restored to their marked position after cleaning.
4.10 Registers, Grilles, Diffusers: It is recommended that all registers, grilles, diffusers and other air distribution devices be removed if possible, properly cleaned, and shall be restored to their previous position.
4.11 Smoke and/or Fire Detection Equipment: Cleaning activities shall not impair, alter or damage any smoke and fire detection equipment located within the facility, or attached to and serving the HVAC system.
4.12 Coil Surface Cleaning: When coil cleaning is performed, both upstream and downstream sides of each coil section shall be accessed for cleaning. When both sides of a coil are not accessible for cleaning then removal and/or replacement may be required.
4.12.1 Preliminary Coil Inspection: A visual inspection of the coil and drain pan shall be conducted prior to cleaning a coil. The data gathered from the preliminary inspection will determine whether Type 1 or Type 2 cleaning is required.
220.127.116.11 If it is determined the coil cannot be properly cleaned through Type 1 methods, Type 2 methods shall be performed.
18.104.22.168 When the preliminary visual inspection reveals suspect microbial matter on any portion of the coil or drain pan, Type 2 cleaning methods shall be performed.
22.214.171.124 When the metal fins of the coil are damaged, deteriorating or showing signs of corrosion, replacement may be necessary. If cleaning will result in further damage to the coil, replacement is recommended.
4.12.2 Type 1 Coil Cleaning (Dry Cleaning): Type 1 methods of coil cleaning shall be used for removing loose dust, dirt or debris collected upon coil surfaces. Negative air machines shall be operated continuously during Type 1 coil cleaning process. The coil shall be isolated from the duct system during the cleaning process to ensure disrupted particulate does not migrate to, or redeposit on, unintended areas. Physical removal of debris may be accomplished through a variety of methods which may include:
4.12.3 Type 1 Post-Cleaning Inspection: This inspection shall be performed after Type 1 coil cleaning has been completed. If debris still remains on the coil or the coil is impacted, Type 2 cleaning shall be performed.
4.12.4 Type 2 Coil Cleaning (Wet Cleaning): Type 2 cleaning methods are appropriate for removing adhered debris on all coil, drain pan and drain line surfaces. Type 2 cleaning shall be performed after non-adhered substance has been removed using Type 1 methods. Type 2 cleaning may include the following methods:
126.96.36.199 The condensate drain pan and drain line shall be cleaned and flushed. The condensate drain pan shall be inspected to verify proper drainage operation before and after cleaning.
188.8.131.52 Cleaning methods and products shall not cause damage to, or erosion of, the coil surface or fins and shall conform to coil manufacturer recommendations when available. It is recommended that only coil cleaning solutions that are as close to pH neutral as possible are used.
4.12.5 Type 2 Post-Cleaning Inspection: Type 2 inspections shall be conducted after completion of Type 2 cleaning methods. If debris still remains on the coil after Type 2 cleaning, the process shall be repeated. When debris cannot be removed using Type 2 cleaning methods, replacement may be necessary.
4.12.6 Measuring the Effectiveness of Coil Cleaning: Visual observation of coil surfaces can be misleading, therefore it is recommended that a static pressure drop measurement be obtained before and after the cleaning process to demonstrate the effectiveness of such efforts.
4.12.7 Inline Coils: Wet cleaning processes using pressurized water and chemical agents are normally required for coil cleaning. Precautions shall be taken to capture rinse water when wet cleaning duct mounted coils without drain pans. Type 1 and/or Type 2 methods shall be used for cleaning inline coils.
4.12.8 Electric Resistance Coils: When cleaning electric resistance coils, the power source to the coils shall be de-energized and locked out/tagged out. When wet process cleaning is used, only non-corrosive detergents shall be used, and the coil shall be rinsed free of chemicals and thoroughly dried prior to being re-energized.
4.13 Control of Odors and Product Emissions: All products used shall comply with any local, regional, state and federal regulations and/or other laws regulating the use of such agents.
4.14 Remediation of Mold Contamination: Remediating mold shall be performed in accordance with the IICRC S520 Standard for Professional Mold Remediation and the cleaning/restoration of the HVAC system provisions as outlined within this Standard.
4.15 Restoration and Repair of Mechanical Systems: Restoration procedures shall only be performed after mechanical cleaning.
4.15.1 HVAC system components subjected to catastrophic events such as fire, smoke, flood, or water damage shall be subject to appropriate restoration procedures as described in Sections 4.23 and 4.24.
4.15.2 Components that are compromised shall be addressed as part of the restoration procedure to the extent possible.
4.15.3 It is recommended that HVAC components be replaced if cleanliness levels specified in this Standard cannot be achieved through mechanical cleaning and restoration methods.
4.16 Surface Treatments: Surface treatments may be used to restore the integrity of material surfaces as an alternative to replacement. Surface treatments shall only be applied after confirming the system has been cleaned and has passed the specified level of cleanliness verification.
4.17 Removal of Mold Contaminated Porous Materials: It is recommended that porous materials with mold growth (Condition 3) be properly removed and replaced. This task shall be followed by surface cleaning using mechanical cleaning methods.
4.18 Cleaning Fibrous Glass Duct System Components: The cleaning of fibrous glass duct liner or duct board present in equipment or air ducts shall be performed in accordance with Section 4.8 of this Standard.
4.18.1 The mechanical cleaning methods selected for duct liner or fibrous glass duct board shall not create abrasions, breaks, or tears to fibrous glass liner or duct board surfaces.
4.19 Resurfacing Fibrous Glass Surfaces: Resurfacing may be considered when thermal acoustic fibrous glass components, including air duct liner or duct board in the HVAC system, are considered friable, or exhibit visual signs of abrasion, degradation, or other undesirable conditions. Resurfacing may also be considered when the project work plan requests smoothing fiber glass surfaces to reduce future particulate collections within the HVAC system.
4.19.1 If resurfacing is to be performed, an assessment shall be made to determine whether the surface of the component will provide a strong, bondable surface for the coating material after undergoing proper mechanical cleaning.
4.19.2 If fibrous glass materials are beyond restoration and deemed unsuitable to support the proper application of a surfacing product or unable to provide a long-term bondable surface, resurfacing shall not be performed.
4.20 Damaged Fibrous Glass Material: When there is evidence of damage, deterioration, delaminating, friable material, such that cleaning or resurfacing cannot restore fibrous glass materials, replacement is recommended.
4.21 Thermal-Acoustic HVAC Insulation Replacement: All metal surfaces of the duct system that have undergone removal of degraded thermal-acoustic material shall have the base surface scraped clean and be free of loose, visible debris prior to installation of new insulation.
4.21.1 In the event the fiber glass removal was due to mold contamination, the base surface shall be cleaned to a Condition 1 status prior to reapplying any fiber glass insulating products.
4.21.2 All materials used for insulation replacement within the HVAC system shall meet or exceed the specifications of the original materials or current applicable codes. Installation of the replacement materials shall be in accordance with the manufacturer's written instructions.
4.21.3 Installation of thermal-acoustic HVAC insulation common to the air stream shall comply with current SMACNA, NAIMA and other applicable codes and standards.
4.21.4 Following completion of the installation of replacement materials, all new fiber glass surfaces shall be capable of meeting NADCA cleanliness verification requirements.
4.21.5 No cleaning process shall be performed that will damage a properly designed, installed, and structurally sound HVAC system and its components, or negatively affect the performance, operation, or normal life expectancy of the system.
4.22 Non-Porous Material Restoration: If the surface conditions of non-porous components, following cleaning, reveal a surface that will continue to contribute particulate, odors or adversely affect the quality of the air moving through the system, restoration is recommended.
4.23 Flooding/Water Damage: All HVAC system surfaces and components subjected to water damage due to flooding shall be evaluated and categorized according to industry recognized methods to determine the ability to salvage and restore, as defined in documents such as the current IICRC Standard S500, Standard and Reference Guide for Professional Water Damage Restoration. To a large extent, the category of water entering the HVAC system will dictate methods of cleaning and environmental engineering controls. Any system components and/or air ducts deemed worthy of salvage shall be thoroughly cleaned.
4.24 Fire/Smoke Damage: All HVAC system components subjected to heat and smoke shall be evaluated for restoration. Any components and/or surfaces unable to withstand proper mechanical cleaning and restoration shall be replaced.
4.24.1 All porous surfaces subjected to fire/smoke damage shall be evaluated following proper mechanical cleaning for friability and odor retention.
4.24.2 Any areas assessed as being friable and/or retaining odors shall be resurfaced or replaced.
4.24.3 Following cleaning, any component surface exhibiting damage due to heat exposure shall be restored to an acceptable condition or replaced.
4.24.4 If there is a question as to whether a system component is contaminated with soot or smoke from a fire, it is recommended that sampling be performed in accordance with documents such as IESO/RIA 6001-2011 Evaluation of Heating, Ventilation and Air Conditioning HVAC Interior Surfaces to Determine the Presence of Fire-Related Particulate as a Result of a Fire in a Structure.
4.25 HVAC System Repair: HVAC components found to have pre-existing damage during the cleaning process shall be documented and brought to the attention of the building owner or representative.
4.25.1 Repair or replacement of malfunctioning mechanical devices is not included in the scope of this Standard. Restoration does not include the sealing of air leaks within duct systems or HVAC equipment.
5.0 Overview: The purpose of cleanliness verification is to determine the presence of particulate. It does not determine microbial contamination and/or the presence of hazardous materials. Cleanliness verification shall be performed on all specified components to verify compliance with this Standard. All components within the project scope of work shall be cleaned, at minimum, to the level of visibly clean or the specified method of cleanliness verification.
5.1 When to Perform Cleanliness Verification: Perform cleanliness verification immediately after HVAC system component cleaning and prior to system operation.
5.2 Description of Method 1 - Visual Inspection: A visual inspection of porous and non-porous HVAC system components shall be conducted to assess if the HVAC system components are visibly clean. An interior surface is considered visibly clean when it is free from non-adhered substances and debris. If a component is visibly clean, then no further cleanliness verification methods are necessary.
5.2.1 Method 1 Inconclusive: If Method 1 - Visual Inspection is inconclusive or disputed, then it is recommended that Method 2 for Porous Surfaces - Surface Comparison Test or Method 2 for Non-Porous Surfaces - NADCA Vacuum Test, be used to verify cleanliness.
5.3 Description of Method 2 for Porous Surfaces - Surface Comparison Test: The Surface Comparison Test may be used to determine cleanliness of porous HVAC component surfaces. The component’s surface conditions are evaluated by comparing visible characteristics of the test surface before and after implementing a specific procedure of contact vacuuming.
5.3.1 Test Method 2 - Surface Comparison Test Protocol: A vacuum brush shall be attached to a contact vacuum and the device shall be running. The brush shall be passed over the surface test area four (4) times, with the brush depressed against the surface being tested using light to moderate pressure (as used in routine cleaning).The testing contact vacuum shall be HEPA-filtered and capable of achieving a minimum of 80 inches of static lift (WC).The contact vacuum shall be fitted with a 2.5 inch round nylon brush attached to a 1.5 inch diameter vacuum hose.
5.3.2 Interpretation of Method 2 - Surface Comparison Test Results: When the procedure described in Section 5.3.1 has been completed, a comparison shall be made to determine if the visible characteristics of the surface have changed significantly. The HVAC component surface is considered to be clean when there is no significant visible difference in the surface characteristics.
5.4 Description of Method 2 for Non-Porous Surfaces - NADCA Vacuum Test: The NADCA Vacuum Test is used for scientifically evaluating particulate levels of non-porous HVAC system component surfaces. Using this procedure, a NADCA Vacuum Test Template is applied to the component’s ducted airside surface. A closed-face vacuum cassette with filter media is attached to a calibrated air sampling pump and the closed-face filter cassette is passed over two (2) 2 cm x 25 cm openings within the template.
At no time can any portion of the vacuum cassette directly contact the component surface being tested. The template is specifically designed to allow the cassette to ride above the surface being tested. Airflow is accelerated through a narrow opening between the template and the test surface of the component, allowing any latent remaining particulate from the component’s surface to be dislodged through increased velocity and impinged onto the filter media within the vacuum cassette. After this procedure is complete, the cassette is prepared and weighed to determine the amount of total debris collected on the filter media.
5.4.1 Test Components: The following describes the materials and test components used to perform Method 2 - NADCA Vacuum Test verification:
5.4.2 Sampling Protocol: Secure the template to the surface to be sampled so that it will not shift position during sample collection (i.e., taped at four corners).
Generally, samples are sent to a laboratory for testing, however, sampling equipment is capable of being brought on to the work site. It is recommended that samples be procured by a qualified individual designated by the client or client’s agent and analyzed by an accredited laboratory.
5.5 Passing Criteria for NADCA Vacuum Test: To be considered clean according to the NADCA Vacuum Test, the net weight of the debris collected on the filter media shall not exceed 0.75 mg/100 cm2.
5.6 Post-Project Documentation: It is recommended that documentation showing compliance with this Standard is provided for all work performed. Documentation can include organized and legible written and visual records.
5.6.1 If the NADCA Vacuum Test is used for cleanliness verification, a copy of the lab results shall be included with this documentation.
5.6.2 If any outside laboratories or testing agencies are used, chain of custody documentation shall be added.
5.6.3 It is recommended that photo images, HVAC plans, and other supporting documents such as submittal forms for materials used and/ or warrantees or guarantees are included as part of Post-Project Documentation.