ANSI/AHAM AC-4
ANSI/AHAM AC-4-2022 evaluates chemical-gas reduction by portable room air cleaners in a specified chamber.
AlignedStandards
CADR Gas Phase: ANSI/AHAM AC-4
ANSI/AHAM AC-4 guidance for chemical-gas reduction studies on portable room air cleaners in a controlled chamber.
For VOC removal claims, plan a protocol matched to the target gas and device, with chamber decay data, controlled gas delivery, and analytical confirmation.
Standard roster
Individual standards in this cluster
ANSI/AHAM AC-4 provides the chemical-gas reduction reference for portable room air cleaners; ARE Labs maps it to chamber setup, natural decay baselines, gas challenge controls, analytical checks, and reporting limits.
Purpose & when to use
Gas-phase chamber studies measure how a room air cleaner reduces selected gaseous contaminants under controlled conditions. ANSI/AHAM AC-4 is the chemical-gas reduction reference for portable room air cleaners. Use this page to scope VOC removal claims, gas delivery, natural decay controls, analytical confirmation, and reporting limits. It also covers EPA indoor air quality context and ISO 17025 quality records where applicable:
- Room air cleaner programs use EPA IAQ context and AHAM chamber framing when VOC reduction claims need controlled decay evidence.
- Gas challenge studies use ISO 17025 quality records to connect MFC settings, natural decay, calibration references, and concentration data.
- Hybrid filtration devices use EPA and AHAM context when sorbent, catalyst, UV, or ionization behavior may affect gas removal.
- Claim reviews use ISO 17025 records to trace ANSI/AHAM AC-4 reduction data to operating mode, chamber conditions, calculations, and interpretation limits.
This page covers room-cleaner gas reduction in a controlled chamber. Stand-alone media and in-duct gas devices need a separate method review. Particulate CADR and bioaerosol reduction fall under their own AHAM methods.
Applicable to
Built for gas-removal chamber decisions
The cluster applies when device operation, chamber background, gas generation, sampling timing, and analytical confirmation determine whether VOC removal evidence is usable.
Standards in this group
What each citation controls
ANSI/AHAM AC-4-2022 addresses chemical-gas reduction by portable room air cleaners. The protocol must identify the gases, device format, chamber conditions, and calculation basis before results support a claim. AHAM AC-1 addresses particulate CADR and AC-5 addresses bioaerosols; ASHRAE gas-media and in-duct device methods are covered in the separate filtration cluster.
AHAM / ANSI
AlignedANSI/AHAM AC-4
Method of Assessing the Reduction Rate of Chemical Gases by a Room Air Cleaner
ANSI/AHAM AC-4-2022 evaluates chemical-gas reduction by portable room air cleaners in a specified chamber. ARE Labs uses the reference to scope selected contaminants, device operation, background and natural decay controls, concentration measurements, reduction calculations, and stated protocol adaptations. Separate by-product investigations require their own analytical plan.
AHAM publisher listing and standards chart verified 2026-10-06; both identify AC-4-2022 as chemical-gas reduction. The effective date was not publicly confirmed.
Laboratory accreditation and method alignment
ARE Labs is ISO/IEC 17025-accredited for its current testing scope. ANSI/AHAM AC-4 is an aligned chemical-gas reduction reference for portable room air cleaners, not an additional accredited scope or product certification. Reports identify chamber conditions, selected gases, analytical methods, adaptations, and any results outside the accredited scope.
- ANSI/AHAM AC-4AlignedChemical-gas reduction reference followed by protocol where applicable.
- ISO 17025AccreditedLaboratory accreditation; method and result coverage follow the current testing scope.
- EPA IAQ contextAlignedClaim context considered without regulatory approval language.
Operational chain
How ARE Labs turns the standards into a study
ARE Labs translates ANSI/AHAM AC-4, EPA indoor air quality context, and ISO 17025 quality records into a chamber protocol that identifies method alignment, adaptations, selected-gas measurements, and the evidence the client receives.
01
Configuration
Define the chamber and device setup
ANSI/AHAM AC-4 setup records document chamber size, mixing, sampling locations, device placement, selected gases, and operating mode, with ISO 17025 traceability to instrument checks.
Protocol setup02
Challenge
Control gas generation
ISO 17025 records tie permeation tubes, certified gases, or MFC delivery to target concentration, stabilization time, and background checks.
Gas setup log03
Operation
Separate natural and device decay
AHAM chamber framing and EPA claim context preserve natural decay baselines, device-on decay runs, temperature, humidity, timing, and operating-state records.
Run record04
Analytics
Confirm gas or by-product data
EPA claim context and ISO 17025 documentation guide FTIR, GC/MS, HPLC, sensor, or other analytical confirmation when the study requires it.
Analytical file05
Reporting
State citation limits
ISO 17025 report review connects ANSI/AHAM AC-4 alignment, selected-gas concentration data, reduction calculations, additional analytical endpoints, deviations, and interpretation limits to the retained study records.
Review-ready reportData quality, QA/QC & documentation
To interpret a gas-phase reduction result, the test conditions and concentration measurements must be traceable. ARE Labs links ANSI/AHAM AC-4 alignment, EPA indoor air quality context, and ISO 17025 documentation to the study records. These include raw instrument files, chamber condition logs, calibration records, calculation workbooks, deviations, and reviewer notes.
Connect setup to citation
ISO 17025 setup records link ANSI/AHAM AC-4 references, selected gases, device operation, chamber configuration, delivery path, and sampling locations to the protocol and instrument checks.
Preserve gas delivery records
ISO 17025 files capture MFC checks, gas certificates, permeation settings, instrument calibration, and any analytical method references.
Separate background and removal
EPA claim context and AHAM-style chamber records keep background, natural decay, device operation, conditions, and run timing visible.
Retain target gas evidence
EPA claim context guides FTIR, GC/MS, HPLC, sensor, or other analytical outputs for target gas and by-product confirmation.
Document method limits
ISO 17025 review notes identify ANSI/AHAM AC-4 alignment, protocol adaptations, additional analytical endpoints, deviations, calculation checks, and report limitations.
Why ARE Labs
ARE Labs connects technical topics to practical study design, method selection, controlled aerosol work, and reportable evidence without turning technical pages into sales pages.
Reviewed byJamie Balarashti - Weston Schaper
QualityDocumented study records
900+Studies Performed
17+Years in operation
300+Clients supported
Common questions
These questions help air cleaner, filtration, and indoor-air-quality teams plan chemical-gas reduction studies under ANSI/AHAM AC-4. The answers cover room-cleaner applications, how this work differs from particulate and bioaerosol methods, and when to add by-product measurements. They also explain which test records are needed to support a device or VOC removal claim.
Q. Which AHAM method covers chemical gases?
A. ANSI/AHAM AC-4-2022 covers chemical-gas reduction by portable room air cleaners. AC-1 addresses particulate CADR; AC-5 addresses bioaerosol reduction. The study plan should identify the selected gases, device format, and intended claim before choosing the method.
Q. Where do ASHRAE filtration methods fit?
A. ASHRAE 145.1 addresses loose granular gas-phase media; 145.2 addresses in-duct gas-phase devices and excludes stand-alone room air cleaners. ASHRAE 52.2 addresses particulate removal by general-ventilation air-cleaning devices. These formats need separate scoping from AC-4 room-cleaner chamber studies.
Q. Does ARE Labs certify CADR claims?
A. No. ARE Labs performs chamber testing and documentation. AHAM certification, regulatory approval, or product listing requires review by the applicable program or authority.
Q. What data does the client receive?
A. Typical outputs include background data, natural decay curves, device-on decay curves, and chemical-gas reduction calculations. Supporting records cover chamber conditions, gas delivery, analytical confirmation, deviations, and method notes. The protocol states the calculation basis and whether a gas-CADR output is appropriate.
Q. Can by-products be measured?
A. Yes, as a separately scoped analytical endpoint. AC-4 chemical-gas reduction results do not establish by-product safety. ARE Labs can add FTIR, GC/MS, HPLC, sensor, or other checks when the protocol requires target-gas or by-product confirmation.
Related services & devices
Related services & devices
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Ducted devices where flow, residence time, and gas challenge control drive protocol design.Read more ->Related clusters
Related standards clusters
Gas-phase CADR work often connects to particulate CADR, emissions background control, calibrated gas delivery, and sorbent breakthrough questions. These neighboring clusters keep the citation logic separated by decision type.
Standards