It is
A proprietary technical reference, published openly, usable in design and in technical specification, whose thresholds are anchored on external references and whose refutation conditions are stated in advance.
About
A reference, its publisher, and the rules it binds itself to.
The XRS scale is the first heuristic published by XALPES LLC. It was built with the discipline of a standard — traceability, reproducibility, falsifiability — and it says on every page what it is not.
Publisher
XALPES LLC — Test Laboratory Division.
XALPES LLC is an independent structure of applied research, product development and technical validation, established in Austin, Texas. The XRS reference was drawn up by its Test Laboratory Division, which conducts the performance characterisation and qualification of filtering media and assemblies.
The reference is published under the sole responsibility of XALPES LLC. It emanates from no national or international standards body, follows no formal consensus process and has no regulatory value. It adopts the presentation conventions of international standards for one purpose: to make it easier to read, cite and confront.
XALPES LLC — Test Laboratory DivisionFile Number 0806424732 — Texas
Registered office: 5900 Balcones Drive, STE 100, Austin, TX 79731, U.S.A.
Correspondence: 7710 N FM 620 BLDG 13-D, Austin, TX 78726, United States
contact@xalpes.com · xalpes.com
Status
A heuristic: between a law and an opinion.
A heuristic is a deliberately simplified decision rule that accepts to lose in exhaustiveness what it gains in usability. It is not a physical law: it is not meant to hold everywhere and always. It is not a standard: it has no regulatory authority and binds no conformity. Nor is it an opinion: it is quantified, reproducible and verifiable by a third party.
It is not
A standard, a regulation, a certification of protection, a medical prescription or an occupational-safety instruction. It classifies breathing comfort only and authorizes no regulated use.
It is not yet
Validated on a human panel. The protocol of Clause 14 is pre-registered with its success criteria; every level declared on the first edition mentions that status.
Trademarks
XRS™ is an adjective.
XALPES™ and XRS™ are trademarks of XALPES LLC, claimed on the basis of use in commerce. The level designations X1 to X6, used in relation to the classification defined by the reference, belong to the same distinctive sign, as do the figurative elements: the XRS logotype composed from the letters of the XALPES logotype, its signature line, the cut-corner badge, the isolated X glyph and the drawing of the numerals 1 to 6. The publication of XRS 001:2026 on the date shown on its cover is documented evidence of first use.
A trademark is an adjective, not a noun. The designation XRS is used exclusively as a qualifier accompanying a generic noun — the XRS scale, an XRS level, the XRS reference — never alone, never plural, never possessive, never as a verb. Repeated nominal use of a mark leads to its degeneration: that is how aspirin, escalator and thermos lost their protection.
The ® symbol is affixed to none of these marks and must not be by any third party; it is reserved for marks actually registered with the competent office. The ™ symbol requires no filing and signals a claim of use.
Governance
What XALPES LLC binds itself to.
Revision by indexed edition
No threshold, qualification or endurance changes without a new edition carrying the justification and the data. Earlier editions stay accessible on this site, marked as superseded.
Refutation before revision
The eight refutation conditions of Clause 15 are the only admissible grounds for moving the scale. Any contestation of a threshold, backed by data, is examined and answered.
Non-discrimination
The reference is applied to every applicant that satisfies it; the price list is public and uniform; no exclusivity is granted on the designation.
Confidentiality of licensees' data
Measured values, bills of materials and reports are confidential. They feed the second edition only after aggregation over at least five licensees and full anonymisation. The obligation survives the contract for five years.
Questions, comments, data
Requests for authorisation, feedback, contestation of a threshold and proposals of new data are addressed to XALPES LLC, Test Laboratory Division.