How should you translate an ISO 11654:1997 acoustic product report that gives αw = 0.70 (MH), sound absorption Class C, octave-band measurements or L/M/H shape indicators? People searching for ISO 11654 translation, weighted sound absorption coefficient meaning, Class A–E acoustic panel ratings, αw versus NRC, or acoustic ceiling test-report translation need more than a literal translation of ‘soundproof’. They need the correct quantity, measurement source, construction and rating to remain attached to one another.
This guide explains how to translate ISO 11654 sound absorption classifications for acoustic panels, wall and ceiling finishes, mineral wool assemblies and room-treatment procurement. We cover the relationship between ISO 354 testing and ISO 11654 rating, αs, αp and αw, low/mid/high frequency information, installation cavities, specimen build-ups, band tables, marketing claims, comparison statements and evidence-based acceptance language. Examples are educational; actual calculations and conformity decisions must use the relevant standards and test records.
ISO currently identifies ISO 11654:1997 as the international standard for rating sound absorption of building sound absorbers, and lists its 2023 review as confirming this edition. Its single-number ratings are useful for communication, but they do not make two different tested assemblies identical or replace frequency-specific acoustic design. A translation can be perfectly grammatical and still mislead a buyer if it changes an absorption Class B into a fire Class B, replaces αw with NRC, or drops the air-gap condition behind the test.
The first distinction: absorption is not sound insulation
A wall product may reduce reflected sound within a room without stopping much sound from travelling through the wall. ‘Sound absorption’ concerns energy absorbed from the incident sound field; ‘sound insulation’ or transmission loss concerns the barrier between spaces. ‘Acoustic treatment’ is broader and may include both concepts. A translator who turns a sound-absorbing panel into a ‘soundproof partition’ changes its promised function. Start with the performance claim and what laboratory measurement supports it. If the source states Class A absorption, preserve the word absorption every time the class appears in a customer-facing table. A specifier may otherwise mistake an interior reverberation treatment for a solution to noise passing between apartments, classrooms or studios. These are different engineering design problems, tested through different methods. The target wording should help the reader choose the correct technology rather than simply sound impressive.
What ISO 11654:1997 owns
ISO 11654:1997 is a rating standard for sound absorbers used in buildings. It provides a way to summarise frequency-dependent absorption performance through a weighted rating and classes. It is not a complete room design method, not a fire-reaction classification, not a speech-intelligibility test and not a measure of airborne sound insulation. Preserve both the number 11654 and the edition 1997 in a translated laboratory claim. The ISO record shows the edition remains current after review in 2023, but an older certificate must still retain whatever method and edition it actually used. The standard’s purpose explains why a product datasheet may have both a compact class and a detailed frequency table. The class helps readers sort products at a high level; the underlying spectrum helps specialists work out whether the absorber meets a particular room or frequency need. Translation should retain both layers if the source offers both.
From ISO 354 measurement to ISO 11654 rating
Measurements and ratings are different stages. ISO 354 addresses measurement of sound absorption in a reverberation room, including the absorption coefficient of building materials and equivalent absorption area of objects in relevant settings. ISO 11654 then provides a rating framework for absorbers. That means the source might cite ISO 354 in the test method column and ISO 11654 beside αw or its class. Do not consolidate the two into a single invented ‘ISO 11654 laboratory measurement’. A test laboratory may also report mounting type, specimen area and installation arrangement that influence measured performance. The rating depends on the evidence produced under those conditions. A translation should distinguish test method, test result, calculated rating and supplier declaration. Many misleading product brochures skip these boundaries. A well-built bilingual datasheet can make the relationship clearer without changing the source evidence.
What αs means and why the subscript matters
An ISO 354 report may use αs for a measured sound absorption coefficient by one-third-octave frequency band, before later treatment into practical octave-band figures. It describes measured frequency-specific behaviour, not a single label covering all audible sound. In digital typesetting, the Greek letter alpha is easily confused with a Latin ‘a’, while the subscript s can disappear during translation or conversion to plain text. Preserve the exact symbol and explain its meaning in a glossary. Do not replace αs with αw because the latter is a derived weighted rating under a different step. If a product appears to absorb better at one frequency than another, a spectrum is exactly where that difference belongs. A translated ‘all-frequency absorption’ claim based on one band would be a major exaggeration. Keep frequency headings and values aligned so readers can inspect the actual band behaviour.
How practical octave-band coefficients αp fit in
The ISO 11654 procedure works with practical absorption coefficients for octave bands, commonly designated αp. These are derived from frequency-band measurement information under the prescribed rating procedure. Do not treat αp as another spelling of the raw αs coefficient. When a report contains a one-third-octave table plus an octave-band rating table, the two may have different row counts and values for legitimate reasons. If translation software automatically sorts frequencies as text, a series like 250, 500, 1000, 2000 and 4000 Hz can end up in the wrong order. Lock the band sequence and keep the physical unit Hz beside its heading. The summary rating depends on the correctly associated band data. Readers comparing two acoustic panels should be able to locate exactly which frequency and which measurement stage each coefficient represents. That is more useful than translating every occurrence of ‘coefficient’ with one undifferentiated phrase.
Read αw as a weighted rating, not a raw observation
The symbol αw names a weighted sound absorption coefficient. Its value comes from a defined reference-curve process, not from measuring one simple proportion with a single microphone. Reported αw values are usually presented in steps of 0.05. A target-language label may explain it as a weighted absorption rating, but the technical symbol should remain unchanged. Beware of the temptation to describe αw = 0.70 as ’70 percent of all sound is absorbed’. That is not a reliable translation of the rating’s meaning: actual absorption varies with frequency, assembly, incident field and other conditions. The number also should not be multiplied by the room’s total floor area as if that alone predicted acoustic comfort. Preserve the method and class context. If the report includes a more detailed frequency curve, keep that curve available rather than letting the weighted value replace everything.
Classes A–E have specific αw bands
In the ISO 11654 classification, Class A corresponds to αw 0.90–1.00; B to 0.80–0.85; C to 0.60–0.75; D to 0.30–0.55; and E to 0.15–0.25. Lower weighted values, 0.10 or below, are not classified under that table. Those bands are not percentages of product ‘quality’ or guarantees of a certain room noise reduction. A category letter is useful only alongside the rating system that defined it. A flooring supplier may use letters for entirely different characteristics, and a construction product can carry fire reaction classes in the same brochure. Do not translate ‘absorption class C’ as ‘fire class C’. Keep the heading ‘ISO 11654 sound absorption class’ at least where the letter first appears and in comparison tables. A panel with αw 0.75 and a panel with αw 0.60 may share Class C but perform differently in the context of a real project.
L, M and H shape indicators restore spectral clues
A bare αw figure condenses complex frequency behaviour. Shape indicators L, M and H can accompany the rating to signal substantial absorption above the reference curve in low, medium or high frequency regions under the standard’s rules. Thus a notation like αw = 0.70 (MH) carries more information than 0.70 alone. It is not a product identifier, mounting code or random footnote. Preserve the letters, brackets and their association with the weighted rating. A target-language glossary can explain L as low, M as medium and H as high, but do not translate the letters themselves into local initials. The notation might appear alongside a plotted curve; check that both display the same classification. Shape indicators do not remove the need to examine actual measured bands when a project has a demanding acoustic target. The translation’s job is to keep these clues rather than simplifying them out of a product brochure.
Why αw and NRC are not interchangeable
The Noise Reduction Coefficient, NRC, is associated with ASTM C423 rating practice and uses a different calculation from the ISO 11654 weighted coefficient. Both are single-number descriptors of sound absorption, but a matching numerical value does not mean the ratings were obtained through identical calculations or carry identical implications. A product datasheet may show both. Preserve the distinct labels and governing standards. Do not convert αw = 0.85 into NRC = 0.85 simply by changing the heading. If an international tender requests one metric while a supplier only provides the other, flag the gap and refer it to the acoustic consultant or test laboratory. A translator cannot infer an ASTM-rated NRC from an ISO αw number alone. This distinction is especially important in global procurement where English-language marketing materials sometimes use ‘acoustic coefficient’ loosely for whichever single number appears on the brochure.
Mounting type, air gap and product build-up
An acoustic panel is not always tested in the same configuration in which buyers intend to install it. The test may include a defined air cavity, suspension arrangement, rigid backing, facing fabric, perforated cover, thickness or insulation layer. These features affect the absorption spectrum. If a ceiling tile rated αw 0.90 was tested with a substantial air gap, do not present the same number as a verified direct-bond rating. Preserve mounting type, cavity depth, thickness, density, surface treatment and fixation detail as stated. A description such as ‘E-200’ may be a mounting descriptor, not an absorption class; check the test record. Translate the assembly, not merely the face material. The target reader should be able to see whether the product being quoted is the same built-up configuration as the tested specimen. Without that connection, even a numerically accurate rating can lead to incorrect purchasing assumptions.
Area and equivalent absorption area do not mean the same thing
A reverberation-room report may express an equivalent sound absorption area for individual objects or spatial absorbers rather than an ordinary surface absorption coefficient for a plane specimen. Both may be associated with ISO 354 measurements, but their units and intended applications differ. Never relabel square metres of equivalent absorption area as a dimensionless αw just because both describe acoustic absorption. If a suspended baffle product has ratings given for each baffle at specific frequencies, do not divide or multiply them into a panel coefficient without an authorised method. Similarly, geometric surface area and acoustically effective area may not match under every mounting. The translation must preserve whether the unit belongs to a coefficient, an area or a tested product quantity. This helps designers avoid double-counting material, particularly where architectural schedules mix ceiling tiles, wall panels and free-hanging objects in one bill of quantities.
Sound absorption ratings are not room reverberation times
ISO 11654 classifies absorbers; ISO 3382 families address measurement of room-acoustic parameters such as reverberation time and clarity. A room’s measured T20, T30 or EDT is not an αw rating of a single wall treatment. If a sales presentation says installing Class A panels will ‘guarantee T30 = 0.4 s’, the translation should not promote that claim without a design model or measured result. Reverberation depends on room volume, existing finishes, geometry, occupied state, distribution of absorbing materials and other factors. Even high-class absorbers do not automatically solve every low-frequency or speech-intelligibility problem. Keep product-level and room-level metrics in separate sections of a bilingual specification. This boundary also protects the site’s existing room-acoustics article from duplication: the job here is translating product ratings and mounting evidence, not teaching a complete room acoustics measurement system.
Marketing claims and their limits
Product language often moves quickly from a test value to promises about comfort, concentration and privacy. Those outcomes may be reasonable goals, but they are not equivalent to the laboratory’s absorption class. An accurate translation distinguishes ‘rated αw 0.90 when installed as tested’ from ‘blocks 90 percent of neighbour noise’ and ‘creates an ideal classroom’. The latter statements require separate support. Translate carefully when the source uses words such as can, may, typically, expected, designed to and guaranteed. These are different levels of commitment. Also retain qualifiers such as ‘according to the attached report’, ‘nominal’, ‘with backing cavity’ and ‘for indicated specimen thickness’. Buyers need to know what is measured, what is inferred and what is advertised. Clarity builds trust more effectively than superlatives, particularly in technical procurement where a misleading acoustic claim can lead to expensive remedial work.
Test edition, specimen identification and report validity
A product can be updated after a test without losing its marketing name. Check whether the report identifies the tested SKU, thickness, density, perforation pattern, fabric wrap, mounting configuration and production revision. The target-language translation should retain those identifiers and the laboratory report number. If the brochure references ISO 11654:1997 but no test sheet is supplied, keep the distinction between a supplier claim and independent test evidence. Likewise, a historical rating is evidence about the historical specimen, not automatic proof for every future variant. If a laboratory withdrew or superseded a report, do not conceal that information. A translated cover sheet should allow an international buyer to match the exact product being purchased to the configuration that generated the advertised result. This is the core of responsible acoustic documentation.
Numbers, punctuation, symbols and plotted curves
Greek α, Latin w, subscripts, degree marks, decimal separators and bracketed shape indicators can be damaged by ordinary text-processing systems. Copy αw, αp and αs accurately. Maintain frequency in Hz and make sure data columns align with 250, 500, 1000, 2000 and 4000 Hz where applicable. If a table uses commas as decimal separators, convert deliberately under an approved locale convention rather than leaving readers to guess. A graph may have frequency on a logarithmic horizontal axis; do not substitute ‘time’ because the curve rises and falls. When republishing plots as images, verify legends, caption references and the exact mounting notes. When accessibility requires a textual alternative, include the values and what the figure actually demonstrates rather than saying ‘chart of acoustic performance’. A technically faithful translation is also a usable document for people reading through assistive technology.
A two-pass translation review for acoustic reports
In the first pass, lock the technical invariants: test standard and edition, lab report number, exact assembly, thickness, mount, air cavity, raw measurement bands, αp, αw, class and L/M/H indicators. Translate the prose around them. In the second pass, read as a building consultant purchasing material for a real project. Is it clear which construction the rating belongs to? Are the standard names correctly mapped? Are absorption, insulation, transmission and room reverberation separated? Have the qualifiers survived? For any claimed equivalence between NRC and αw, require independent technical review. The first pass guards source fidelity; the second guards practical usability. The resulting article or product datasheet should not bury limitations beneath unexplained numbers. Readers should be able to locate the exact evidence supporting each performance statement before a contract is signed.
AI translation and automated datasheet production
AI tools can draft product descriptions and suggest bilingual equivalents for ‘acoustic panel’, ‘absorption coefficient’, ‘mounting cavity’ and ‘reverberation room’. They can also hallucinate an αw result from a class letter, convert αw to NRC by assumption, or remove L/M/H indicators because they look decorative. Treat every generated line as a proposal. Verify against the laboratory source, original product build-up and approved glossary; do not rely on a fluent paragraph as evidence. Protect client drawings and unpublished test data appropriately. Automated catalogues should store numerical fields separately from translatable prose and display the governing standard next to each performance rating. If the system transforms decimal punctuation, test both export and website rendering. One missing Greek subscript or one overwritten air-cavity condition can do more damage to procurement than a dozen awkward but harmless sentences.
How this topic fits within translation and language learning
This article solves one specialised search intent: preserving meaning when ISO 11654 acoustic absorption ratings cross languages. It does not replace the general translation mechanism, teach all vocabulary, or become a complete room-acoustics manual. A learner who does not understand ‘weighted’, ‘coefficient’, ‘frequency’ or ‘cavity’ may need a vocabulary lesson; a specialist who understands the concepts but cannot transport an ISO rating safely needs a controlled technical translation workflow. English readers may also need help with restrictive clauses: ‘when installed with a 200 mm cavity’ limits the rating’s applicability and cannot be dropped as incidental detail. Keep the role of each neighbouring learning system explicit. The central transfer problem here is an invariant: the receiving buyer must read the same product, assembly, measurement and claim as the original author documented.
Twenty-five acoustic datasheet and specification translation cases
1. Class A means absorption, not fire
Source context: A ceiling brochure shows ‘ISO 11654 absorption Class A’ beside a separate reaction-to-fire classification.
Common mistranslation: The target version merges them into ‘fire-resistant Class A acoustic panel’.
Better rendering: Retain ISO 11654 sound absorption Class A as its own field and separately label fire performance.
Reason: Identical letters can belong to different rating systems. The category name must stay attached to its standard and measured characteristic.
2. αw = 0.70 (MH)
Source context: The datasheet gives αw 0.70 with the shape indicators MH.
Common mistranslation: The translation removes the brackets and calls MH a manufacturing batch code.
Better rendering: Preserve αw = 0.70 (MH) and explain the medium/high-frequency indicators.
Reason: The bracketed letters retain spectral information that the single weighted figure cannot convey.
3. Raw αs versus weighted αw
Source context: The ISO 354 table reports one-third-octave αs values and the product summary reports αw.
Common mistranslation: Both become ‘average sound absorption’ in the target language.
Better rendering: Keep separate symbols, band descriptions and calculation stages.
Reason: A measured band coefficient and a weighted rating do not have the same derivation or intended use.
4. Class C with two different αw values
Source context: Two products have αw values of 0.60 and 0.75, both assigned Class C.
Common mistranslation: A marketing comparison says they have identical acoustic performance.
Better rendering: Translate the shared class but preserve the different αw figures and spectra.
Reason: Classification compresses a range; equality of class is not proof of equality of frequency response.
5. Class B and Class A boundary
Source context: A revised specimen reports αw 0.85 while the older product is αw 0.90.
Common mistranslation: The translated brochure assigns Class A to both versions.
Better rendering: Keep Class B for the 0.85 result and Class A for the 0.90 result where applicable.
Reason: The class boundary is specific. A small numerical change can change the category, and the versions must remain traceable.
6. Not classified below Class E
Source context: A report shows αw = 0.10 and does not assign a class.
Common mistranslation: The translation upgrades it to sound absorption Class E.
Better rendering: Retain the non-classified status under the ISO 11654 scheme.
Reason: The scale is not an arbitrary alphabet: Class E has a defined lower band, and the translator cannot fill a class for convenience.
7. NRC shown alongside αw
Source context: The supplier provides an NRC from a separate ASTM-based document and an αw from ISO 11654.
Common mistranslation: A bilingual spreadsheet overwrites the NRC header with αw.
Better rendering: Preserve both metrics with their respective standard references.
Reason: The same-looking decimal does not convert one calculation method into another.
8. E-200 mounting notation
Source context: The tested ceiling system used a designated 200 mm cavity arrangement.
Common mistranslation: The translated description drops the cavity and advertises the same result for direct glue-on installation.
Better rendering: Keep the full mounting arrangement and tested system name.
Reason: The absorption rating is conditional on construction. Buyers must know whether the proposed installation matches it.
9. Panel thickness change
Source context: A 50 mm sample is tested, while the catalogue offers a new 25 mm variation.
Common mistranslation: The translation applies the 50 mm sample’s αw to the new product without qualification.
Better rendering: Retain thickness, SKU and exact tested variant.
Reason: Changing thickness can change absorption characteristics; translation should not authorise an untested extension.
10. Fabric-faced assembly
Source context: The source rating is for a board with a specified fabric and backing.
Common mistranslation: The target brochure calls the result a bare-board property.
Better rendering: Translate the tested build-up rather than only the substrate.
Reason: Facing and backing are part of the sound-absorbing assembly and may affect measured performance.
11. 250 Hz versus 2500 Hz
Source context: A figure labels one frequency band 250 Hz.
Common mistranslation: The target table acquires an extra zero during reformatting.
Better rendering: Audit frequency labels against the original table and plot.
Reason: Moving a value into a higher frequency band misrepresents which sounds the product absorbs best.
12. Curve converted to room claim
Source context: A frequency-dependent panel coefficient is accompanied by a room photograph.
Common mistranslation: The caption says the photo proves a specific room reverberation time.
Better rendering: Keep product absorption evidence distinct from any room measurement or prediction.
Reason: A photograph cannot replace a room-acoustics assessment. The target claim must not expand the laboratory evidence.
13. One-third-octave versus octave bands
Source context: The source includes detailed one-third-octave measurements and a five-band rating summary.
Common mistranslation: The translation calls both tables ‘five-frequency results’.
Better rendering: Label the frequency resolution and stage of processing separately.
Reason: Readers need to distinguish original measurement data from the practical coefficients used for rating.
14. αw read as 70 percent sound blocked
Source context: A product holds αw 0.70.
Common mistranslation: A sales translation says the product blocks 70% of sound passing through a wall.
Better rendering: Use ‘weighted sound absorption coefficient’ and preserve the test method.
Reason: Absorption is not transmission loss, and αw is not a universal fraction of transmitted sound prevented.
15. Speech privacy promise
Source context: A wall treatment has a good absorption class.
Common mistranslation: The target text guarantees that confidential conversations cannot be heard outside.
Better rendering: Translate only the claimed room-treatment function unless privacy performance is independently supported.
Reason: Privacy depends on barriers, leakage and system design, not on a single absorption rating.
16. Equivalent absorption area
Source context: A free-hanging baffle uses m² of equivalent absorption area per object.
Common mistranslation: The target chart treats the value as a dimensionless αw.
Better rendering: Retain the measurement quantity, unit and object basis.
Reason: Object absorption area and panel coefficients are different; a buyer cannot use them interchangeably without design context.
17. Mounting detail in footnote
Source context: An unusually strong low-frequency response is qualified by an installation-cavity footnote.
Common mistranslation: The translated table keeps the curve but removes the footnote.
Better rendering: Preserve the qualification beside the reported curve.
Reason: The footnote is part of the meaning of the measurement, not a dispensable editorial aside.
18. Test report versus marketing promise
Source context: The lab says ‘measured under specified conditions’.
Common mistranslation: The translation changes the sentence to ‘guaranteed performance in any room’.
Better rendering: Carry the specified conditions and avoid universal guarantees.
Reason: A measured test setup supports a narrower proposition than every real-world installation.
19. Greek glyph lost in PDF export
Source context: The original αw becomes plain ‘aw’ after document conversion.
Common mistranslation: The target reader sees an unexplained product code.
Better rendering: Use Unicode or verified mathematical typesetting and check the final PDF.
Reason: The symbol identifies a recognised acoustics rating; transcription quality is part of technical fidelity.
20. High-frequency indicator ignored
Source context: A rated product carries the indicator H after the weighted coefficient.
Common mistranslation: The translator deletes H as a redundant English letter.
Better rendering: Retain H and explain its role in the standard’s frequency-shape notation.
Reason: Removing the indicator discards information about the curve even when αw remains unchanged.
21. Reverberation room confused with final room
Source context: The test used a laboratory reverberation room to measure absorption.
Common mistranslation: The target brochure says the product was tested in the customer’s building.
Better rendering: Preserve the laboratory setting and separate any subsequent project evaluation.
Reason: The term ‘room’ is not sufficient to establish which physical space was studied.
22. Supplier claim without attached certificate
Source context: An online catalogue claims Class A but supplies no identified report.
Common mistranslation: The target-language page calls the figure independently verified.
Better rendering: Keep the supplier’s claim and state the absence of a linked test record when relevant.
Reason: Translation cannot create independent evidence. The buyer should know what documentation was actually supplied.
23. Panel and baffle in one schedule
Source context: An architectural schedule lists ceiling tiles and suspended baffles.
Common mistranslation: The translation gives both product types the same coefficient unit and test quantity.
Better rendering: Keep plane-absorber and object-based metrics tied to their products.
Reason: The specifier needs correct quantity bases to avoid comparison or material-count errors.
24. Revised installation specification
Source context: The architect removes the ceiling cavity after procurement.
Common mistranslation: The bilingual handover retains the previous rated installation statement without an update note.
Better rendering: Distinguish the rated tested assembly from the revised proposed installation.
Reason: A design change can break the connection between claimed performance and what will be constructed.
25. Class label without governing standard
Source context: A generic product listing says only ‘acoustic class B’.
Common mistranslation: The translated copy assumes ISO 11654 and adds αw = 0.85.
Better rendering: Retain the ambiguous source claim and request the standard and report.
Reason: Class B is not self-defining. Inventing the standard and the numerical result would create a false technical specification.
Frequently asked acoustic translation questions
Can I translate αw as an NRC value?
No. ISO 11654 αw and ASTM-associated NRC use different rating methods. Keep both symbols and the source standards distinct.
Does Class A mean a product is soundproof?
No. Class A refers to sound absorption under the ISO 11654 scheme, not airborne sound insulation or a guarantee of privacy.
Is αw = 0.70 exactly 70 percent absorption at all frequencies?
No. It is a weighted single-number rating derived by a defined process from frequency data and does not describe every frequency or installation.
What are the shape indicators L, M and H?
They signal specific spectral characteristics relative to the rating reference curve in low, middle and high frequency regions. Keep them attached to αw.
Why is the air cavity important?
Mounting and cavity depth can change measured absorption. The rating belongs to the tested assembly and must not silently be transferred to a different build-up.
Why do test reports show ISO 354 and ISO 11654?
ISO 354 is the measurement method; ISO 11654 provides a rating procedure. Both references may legitimately appear in the same technical document.
Is a Class C panel always worse than a Class B one for every room?
The class compares weighted ratings, not suitability for every acoustic objective. Frequency response, quantity and installation affect design suitability.
Who resolves missing or contradictory acoustic ratings?
The laboratory, product technical owner and appointed acoustician or specification authority. A translator should record the ambiguity rather than inventing a performance claim.
Authoritative reading, learning routes and final checks
The reference owners for this technical topic are ISO 11654:1997, sound absorption rating and ISO 354:2003, reverberation-room measurement. Use their licensed texts and the relevant laboratory records for normative calculation or compliance decisions. The Master Art of Translation remains the general cross-language methodology owner; this page covers the narrower product-rating problem.
For learning terminology and word meanings, visit the protected Vocabulary Learning Hub. For English modifiers, conditions, clarity and reading, use How English Works. Neither pathway substitutes for specialist acoustic analysis or rewrites an existing canonical article.
Before releasing a multilingual acoustic specification, compare the final target against the source for every product ID, specimen thickness, mounting cavity, method edition, αs/αp/αw distinction, frequency band, class, shape indicator, supplementary NRC rating, certification status and conditional sentence. Read the result as a purchaser: can the reader identify exactly what was tested, what it demonstrated and how that evidence applies to the proposed installed assembly? A translation is ready only when its technical limits travel with its benefits.