kSIST FprEN 2948:2026

• Abstract:

  This document specifies the characteristics of tab washers, in heat resisting steel, passivated, for maximum operating temperature 650 °C, for aerospace applications.; Their use under hexagon head bolts is conditional upon the user accepting the possibility of some interference.

• Status: Not Published
• Public Enquiry End Date: 24-Feb-2026
• ICS: 49.030.50 - Washers and other locking elements
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 5020 - Formal vote (FV) (Adopted Project)
• Start Date: 12-Oct-2026
• Due Date: 30-Nov-2026
• Completion Date: 13-Oct-2026
• Ref Project: FprEN 2948 - Aerospace series - Washers, tab, in heat resisting steel, passivated

• Revises: SIST EN 2948:2001 - Aerospace series - Washers, tab, in heat resisting steel, passivated
• Effective Date: 23-Jul-2025

kSIST FprEN 2948:2026 is the SIST version of draft European Standard prEN 2948 for aerospace tab washers in heat resisting steel, passivated. It specifies the characteristics of these washers for aerospace applications and a maximum operating temperature of 650 °C. The standard is aimed at designers, manufacturers, inspectors, and buyers who need a defined locking washer for this service.

What does kSIST FprEN 2948:2026 specify?

kSIST FprEN 2948:2026 specifies the characteristics of tab washers made from heat resisting steel with a passivated surface finish for aerospace use. It also states a practical limitation: use under hexagon head bolts is conditional and may involve interference, so fit should be checked in the intended assembly.

The document is organized into the following main clauses and annex:

Part	What it covers
Clause 1	Scope
Clause 2	Normative references
Clause 3	Terms and definitions
Clause 4	Required characteristics
Clause 5	Designation
Clause 6	Marking
Clause 7	Inspections and tests
Clause 8	Quality assurance
Annex A	Bending test and installation example

Annex A is informative and gives a practical example of bending and installation.

What are the key requirements of kSIST FprEN 2948:2026?

The main requirements are in Clause 4 through Clause 8. Together they define the part geometry, the material and surface condition, how the part is named and marked, and how it is checked before delivery.

Geometry, dimensions, and mass

Clause 4.1 says the configuration, dimensions, and masses shall follow Figure 1 and Table 1. The dimensions and tolerances are in millimetres and apply after surface treatment. In practice, that means inspection should be based on the finished part, not the pre-treated blank, and drawings need to match the table exactly. Table 1 covers diameter codes from 040 to 200.

Material and surface treatment

Clause 4.2 requires the material to comply with EN 2175. Clause 4.3 requires the surface treatment to comply with EN 2516. For users, this means material selection and passivation are not left open to local practice - they are tied to named aerospace standards.

Designation and marking

Clause 5 gives the designation format, with an example of TAB WASHER EN 2948-080. Clause 6 requires marking in accordance with EN 2424, style G. In practice, this helps procurement and traceability because the part can be identified consistently on drawings, labels, and delivery documents.

Inspection and test checks

Clause 7.1 requires visual examination for burrs, scratches, and cracks. The sampling quantity depends on delivered quantity, so incoming acceptance needs a sampling plan matched to the lot size. Clause 7.2 requires a bend test on 0.1 % of the washers to be inspected, with a minimum of three parts. The washers are assembled in normal operating conditions, then the locking tabs are folded and straightened twice; they must remain free from cracks.

Quality assurance

Clause 8 requires the manufacturer to be an approved production organization for aerospace products and to have a maintained quality management system. It also requires use and documentation of a qualification procedure for aerospace standard products, unless customer and supplier agree otherwise. In practice, this links the part to controlled aerospace production and formal qualification, not ad hoc manufacture.

What terms does kSIST FprEN 2948:2026 define?

kSIST FprEN 2948:2026 does not list formal terms in Clause 3, but it uses several key technical terms throughout the document:

• Tab washer - a washer with a locking tab used to help prevent loosening in service.
• Passivated - surface-treated in accordance with EN 2516 to support corrosion resistance and cleanliness.
• Heat resisting steel - the steel material specified for use at elevated temperature.
• Hexagon head bolts - the bolt type named in the scope where interference can occur.
• Quality management system - the organized system used to control aerospace production quality.
• Qualification procedure - the documented procedure used to demonstrate that the product meets the specified tests.

Who uses kSIST FprEN 2948:2026?

kSIST FprEN 2948:2026 is used in aerospace supply chains where tab washers are specified, made, inspected, or purchased. Engineers use it when selecting the washer geometry and checking installation constraints. Manufacturers and inspection teams use it for material control, surface treatment, marking, and acceptance testing. Quality managers and buyers use it to align procurement, traceability, and product qualification with an aerospace standard.

What changed in kSIST FprEN 2948:2026 from the previous edition?

kSIST FprEN 2948:2026 supersedes EN 2948:1996. The changes stated in the document are:

• Clause 3, “Terms and definitions,” was added.
• Clause 8, “Quality assurance,” was updated.
• Annex A, “Bending test and installation example,” was added.

Which standards are used with kSIST FprEN 2948:2026?

Standard	What it contributes
EN 2175	Material specification for the heat resisting steel
EN 2424	Marking of aerospace products
EN 2516	Passivation of corrosion resisting steels and decontamination of nickel or cobalt base alloys
EN 9100	Example of a quality management system for aviation, space and defence organizations
EN 9133	Example of a qualification procedure for aerospace standard products

EN 2175, EN 2424, and EN 2516 are normative references in the text. EN 9100 and EN 9133 are cited in Clause 8 and the bibliography as examples for quality assurance and qualification.

What does the kSIST FprEN 2948:2026 document contain?

The document contains Figure 1 and Table 1 for configuration, dimensions, and masses. It also contains Table 2 for visual examination sampling, which supports inspection planning by delivered quantity. Annex A adds Figure A.1, Table A.1, and Figures A.2 and A.3 to show bending and installation examples, including the handling of the tab during folding and installation. These parts are used for design definition, incoming inspection, bending test planning, and practical installation guidance.

SLOVENSKI STANDARD
oSIST prEN 2948:2026
01-februar-2026
Aeronavtika - Podložke, z zatičnim jezičkom, iz toplotno odpornega jekla,
pasivirane
Aerospace series - Washers, tab, in heat resisting steel, passivated
Luft- und Raumfahrt - Sicherungsblech mit Lappen aus hochwarmfestem Stahl,
passiviert
Ta slovenski standard je istoveten z: prEN 2948
ICS:
49.030.50 Podložke in drugi blokirni Washers and other locking
elementi elements
oSIST prEN 2948:2026 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 2948:2026
oSIST prEN 2948:2026
DRAFT
EUROPEAN STANDARD
prEN 2948
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2025
ICS 49.030.50 Will supersede EN 2948:1996
English Version
Aerospace series - Washers, tab, in heat resisting steel,
passivated
Luft- und Raumfahrt - Sicherungsblech mit Lappen aus
hochwarmfestem Stahl, passiviert
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

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United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 2948:2025 E
worldwide for CEN national Members.

oSIST prEN 2948:2026
prEN 2948:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Required characteristics . 4
4.1 Configuration – Dimensions – Masses . 4
4.2 Material . 4
4.3 Surface treatment . 4
5 Designation . 6
6 Marking . 6
7 Inspections and tests . 6
7.1 Appearance . 6
7.2 Bend test . 6
8 Quality assurance . 6
Annex A (informative) Bending test and installation example . 7
Bibliography . 10

oSIST prEN 2948:2026
prEN 2948:2025 (E)
European foreword
This document (prEN 2948:2025) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 2948:1996.
This document includes the following significant technical changes with respect to EN 2948:1996:
— Clause 3 “Terms and definitions” added;
— Clause 8 “Quality assurance” updated;
— Annex A “Bending test and instal
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