Acoustic testing and calibration standards
Most pages about standards paraphrase the standard. This one tells you what ALT does with it, what specimen we need, and whether the result comes with accreditation behind it.
ISO
| Standard | What ALT does with it | Status |
|---|---|---|
| ISO 354 Acoustics — Measurement of sound absorption in a reverberation room | Sound absorption coefficient of building and acoustic products on a 10–12 m² specimen. Reported per one-third-octave band with αw to ISO 11654. See the related service | Traceable — not in accredited scope |
| ISO 11654 Sound absorbers for use in buildings — Rating of sound absorption | Converts the measured absorption curve into the single-number rating αw and absorption class A–E. See the related service | Traceable — not in accredited scope |
| ISO 10534-2 Determination of sound absorption coefficient and impedance in impedance tubes — Transfer-function method | Normal-incidence absorption and impedance on small samples. Fast and cheap, which makes it the right tool for prototype A/B comparison. See the related service | Traceable — not in accredited scope |
| ISO 10140-2 Laboratory measurement of sound insulation of building elements — Airborne sound insulation | The ISO route to the same result, rated as Rw to ISO 717-1. Choose this when your buyer specifies ISO or EN. See the related service | Traceable — not in accredited scope |
| ISO 717-1 Rating of sound insulation — Airborne sound insulation | Single-number rating Rw with spectrum adaptation terms C and Ctr. See the related service | Traceable — not in accredited scope |
| ISO 10140-3 Laboratory measurement of sound insulation of building elements — Impact sound insulation | Impact sound performance of floor coverings and floating floors, rated Ln,w or ΔLw. See the related service | Traceable — not in accredited scope |
| ISO 3744 Determination of sound power levels using sound pressure — Engineering methods for an essentially free field over a reflecting plane | The workhorse method for machinery noise declarations, including EU Directive 2000/14/EC and the Machinery Regulation (EU) 2023/1230. See the related service | Traceable — not in accredited scope |
| ISO 3745 Determination of sound power levels — Precision methods for anechoic and hemi-anechoic rooms | Precision grade 1 sound power in the anechoic chamber, for products where the declared figure has to withstand challenge. See the related service | Traceable — not in accredited scope |
| ISO 3741 Determination of sound power levels — Precision methods for reverberation test rooms | Sound power in the reverberation room, suited to broadband sources and products that are awkward in a free field. See the related service | Traceable — not in accredited scope |
| ISO 26101-1 Acoustics — Test methods for the qualification of the acoustic environment | Qualification of our free-field environment. This is the evidence that the chamber performs as claimed. See the related service | Traceable — not in accredited scope |
| ISO 9053 / EN 29053 Acoustics — Determination of airflow resistance | Airflow resistivity of porous absorbers — the single most predictive material parameter for absorption performance. See the related service | Traceable — not in accredited scope |
| ISO 16063 series Methods for the calibration of vibration and shock transducers | Accelerometer and vibration meter calibration by comparison against a reference transducer. See the related service | Traceable — not in accredited scope |
| ISO 4869-1 Hearing protectors — Subjective method for the measurement of sound attenuation | Attenuation of hearing protectors. Relevant to hearing conservation programmes under Thai occupational noise rules. See the related service | R&D measurement — not accredited |
ASTM
| Standard | What ALT does with it | Status |
|---|---|---|
| ASTM C423 Sound absorption and sound absorption coefficients by the reverberation room method | The North American equivalent of ISO 354, reporting NRC and SAA. Choose this when your buyer specifies ASTM. See the related service | Traceable — not in accredited scope |
| ASTM E1050 Impedance and absorption of acoustical materials using a tube, two microphones and a digital analysis system | Two-microphone impedance tube method, the ASTM counterpart to ISO 10534-2. See the related service | Traceable — not in accredited scope |
| ASTM E2611 Normal incidence sound transmission of acoustical materials based on the transfer matrix method | Normal-incidence transmission loss on small samples — a useful screening step before committing to a full 10 m² partition test. See the related service | Traceable — not in accredited scope |
| ASTM E90 Laboratory measurement of airborne sound transmission loss of building partitions and elements | Full-size partition transmission loss in the reverberation room pair, rated as STC to ASTM E413. See the related service | Traceable — not in accredited scope |
| ASTM E413 Classification for rating sound insulation | Converts the measured transmission loss curve into the single-number STC rating. See the related service | Traceable — not in accredited scope |
| ASTM E492 Laboratory measurement of impact sound transmission through floor-ceiling assemblies using the tapping machine | The ASTM route to IIC. See the related service | Traceable — not in accredited scope |
| ASTM E477 Laboratory testing of ducted air distribution systems and air terminals for aerodynamic and acoustical performance | Insertion loss and regenerated noise of silencers and air terminals. See the related service | R&D measurement — not accredited |
IEC
| Standard | What ALT does with it | Status |
|---|---|---|
| IEC 61672-3 Electroacoustics — Sound level meters — Periodic tests | Our accredited method for periodic testing of Class 1 and Class 2 sound level meters, verifying conformity to the specification in IEC 61672-1. This is the standard behind every legally usable noise measurement in Thailand. See the related service | ISO/IEC 17025 accredited |
| IEC 61094-2 cl. 5.3 Measurement microphones — Pressure calibration of laboratory standard microphones | Pressure sensitivity at 250 Hz and 1 kHz. Accredited, with a CMC of 0.15 dB. See the related service | ISO/IEC 17025 accredited |
| IEC 61094-6 cl. 5.3 Measurement microphones — Electrostatic actuators for frequency response determination | Frequency response by electrostatic actuator, accredited from 100 Hz to 20 kHz with CMCs from 0.040 dB to 0.55 dB depending on band. See the related service | ISO/IEC 17025 accredited |
| IEC 60942 Electroacoustics — Sound calibrators | Accredited calibration of sound calibrators: sound pressure level 70–135 dB, frequency 31.5 Hz–16 kHz, and total distortion plus noise. See the related service | ISO/IEC 17025 accredited |
| IEC 60704 series Household and similar electrical appliances — Test code for the determination of airborne acoustical noise | Appliance noise declarations. The figure that appears on EU energy labels for air conditioners, washing machines, dishwashers and refrigerators. See the related service | Traceable — not in accredited scope |
| IEC 60268-16 Sound system equipment — Objective rating of speech intelligibility by speech transmission index | Speech transmission index for public address, alarm and voice evacuation systems. See the related service | R&D measurement — not accredited |