DEF STAN 00-35 testing is the process of proving, with documented evidence, that defence equipment survives the climatic, mechanical, chemical and biological conditions of its service life. The standard is now published as DEF STAN 00-035. It is a UK Ministry of Defence handbook, and you meet its requirements by tailoring test methods to your equipment’s life cycle, then having the work done in a UKAS-accredited laboratory whose scope covers the issue your contract names.
We make precision glass for defence, aerospace and medical programmes, so we see this standard from the component side. Windows, display covers and sensor glass are tested as part of larger assemblies, and the way an RFQ is written decides whether that testing goes smoothly. This guide explains the standard, the route to compliant results, and what glass specifiers should settle early.
TL;DR
- DEF STAN 00-035 is a multi-part MOD handbook. Part 3 holds the test methods. Parts 1 and 2 explain how to derive a test programme that justifies them.
- Choose test methods from your documented service life, not from a menu. Applying the harshest severities without justification is a common and costly mistake.
- Use a UKAS-accredited laboratory and check that its schedule lists the exact issue of the standard and the exact tests your contract needs.
- State the required issue in the contract and RFQ. Mismatches between contract and lab accreditation are a frequent cause of delay.
- For glass, define coatings, edge finish, mounting and traceability before testing starts, so results transfer to production parts.
Table of Contents
- What DEF STAN 00-035 is
- How the parts fit together
- Avoiding over-testing
- Working with international standards
- Choosing a UKAS-accredited laboratory
- Name the issue in your contract
- Test early, not only at the end
- What this means for glass components
- Perspective: what we see from the glass side
- A practical RFQ checklist for glass
- Custom glass for defence programmes
- FAQ
- Sources
What DEF STAN 00-035 is
DEF STAN 00-035 is titled Environmental Handbook for Defence Materiel. According to the current listing for Part 3, the standard has six parts:
- Part 1: Control and Management
- Part 2: Trials Programme Derivation
- Part 3: Test Methods
- Part 4: Natural Environments
- Part 5: Induced Mechanical Environments
- Part 6: Induced Climatic, Chemical and Biological Environments
Part 3 was reissued as Issue 7 in March 2025, according to Intertek Inform’s catalogue entry, and it supersedes Issue 6 of 2023. Older contracts often still cite earlier issues, which matters later in this guide.
The handbook contains environmental descriptions, a range of test procedures and default test severities for conditions that defence materiel may meet during its life, as the Part 2 introduction describes. Test methods carry codes. Mechanical tests begin with M (for example M1 for vibration) and climatic tests with CL, as seen on laboratory accreditation schedules.
How the parts fit together
Part 3 cannot be used in isolation. The methods are prescriptive about how a test is run, but whether you should run a given test, and at what severity, comes from the derivation work in Parts 1 and 2.
In practice that means:
- Define the life cycle. Record storage, transport, handling and operational use, including duration and location.
- Derive the environments. Map each phase to the environmental conditions it creates.
- Select and tailor the tests. Choose methods from Part 3 and justify severities and durations.
- Write a test instruction. Turn the generic method into a project-specific document the laboratory can follow.
- Keep the evidence. Results feed the environmental case that supports acceptance of the equipment.
The approach replaces older ruggedness-style testing with evidence-based simulation of the equipment’s life. Treating the handbook as a menu of tests to tick off is the usual route to a non-compliant or over-engineered product.
Avoiding over-testing
The most common error practitioners describe is applying the most severe levels in the handbook with no justification. The standard expects tailoring: severities and durations follow the documented environmental profile of the product’s real service.
Over-testing has two costs. Development becomes more expensive, and equipment can be damaged by test levels it will never meet in service. For glass, an unjustified shock or thermal cycling severity can crack a part that would be perfectly adequate in the field, sending a team into a redesign that was never needed.
Working with international standards
The MOD’s stated intent is to keep the handbook compatible with international agreements, in particular NATO STANAG 4370 and IEC 60068, as the Part 3 preface explains. This helps if you supply both defence and commercial markets. A test run once against a method that aligns with an IEC counterpart may serve more than one customer, which avoids duplicated effort.
UKAS schedules show the same overlap. Some laboratories list DEF STAN methods next to BS EN 60068 tests, as one schedule of accreditation does for bump testing. If your programme also calls for US requirements, our guide to writing RFQs that pass MIL-STD-810 testing covers that side.
Choosing a UKAS-accredited laboratory
For results that a defence customer will accept, use a laboratory accredited by the United Kingdom Accreditation Service to ISO/IEC 17025:2017. Accreditation is granted against a schedule, and the schedule is what counts, not the logo.
For example, the UKAS schedule for the BAE Systems Global Combat Systems Munitions environmental test facility at Bishopton, issued in August 2026, lists specific tests such as M1 and M19 and various climatic methods. Another laboratory’s schedule, published by UKAS, lists tests CL1 and CL2 against Issue 3 (1999) and Issue 4 (2006), but only test CL2 against Issue 5 (2017). Two laboratories can both say they test to DEF STAN 00-035 and still cover very different ground.
Before you book, check these points on the schedule:
| Check | Why it matters |
|---|---|
| Issue of the standard | Accredited results apply only to the issues listed. |
| Individual test codes | A lab may hold CL methods but not the mechanical ones you need. |
| Size and mass limits | Large assemblies may exceed the stated capability. |
| Item types covered | Schedules group scope by product category. |
| Issue date of the schedule | Scopes change, so use the current version. |
Testing outside an accredited scope may not be accepted for formal defence project qualification. If a test you need is not covered, ask the customer’s design authority early whether they will accept an alternative route.
Name the issue in your contract
Procurement delay often comes from a simple mismatch: the contract cites one issue, and the laboratory is accredited for another. Contracts show how specific the references are. One Contracts Finder notice, for instance, cites Part 4 at Issue 6, dated 14 December 2023.
Write the issue number and date into every RFQ and purchase order, and confirm before award that your chosen laboratory’s schedule lists it.
Test early, not only at the end
Testing providers increasingly push early-stage qualification. Element describes this approach as a way to find risk through targeted early tests tied to project requirements, rather than discovering it at final qualification. The logic is sound for any programme: a failure on a prototype costs a revision, while a failure at formal qualification can cost months.
What this means for glass components
Glass is rarely tested alone. It sits in a housing, behind a bezel, bonded to a display or fixed over a sensor. Yet the properties that decide whether it survives are set at component level. Settle these before testing:
- Material and strengthening. Chemically strengthened or toughened glass behaves differently under shock and thermal cycling from annealed glass. Our defence glass materials list and glass selection guide for defence set out the options.
- Edge finish and machining. Edge condition influences where cracks start. See our notes on CNC glass machining for RFQs.
- Coatings. Anti-reflective and anti-glare layers must survive humidity, temperature cycling and abrasion.
- Corrosive environments. Marine and coastal programmes need to consider salt fog testing alongside the climatic methods.
- Mounting and sealing. If the assembly is sealed, review hermeticity testing methods.
- Batch traceability. Test samples must be demonstrably representative of production lots.
For touch and display assemblies, our defence-grade touch display workflow shows how to keep these decisions stable through new product introduction.
Perspective: what we see from the glass side
Most test failures we hear about with glass are not mysteries of physics. They come from specifications that were fixed late. A programme chooses its glass, then discovers during environmental testing that the coating, edge finish or mounting was never defined against the real environmental profile.
Our view is that glass belongs in the environmental case from the first draft. Give the component supplier the tailored severities, not just the standard’s name. “Tested to DEF STAN 00-035” is not a specification. A usable RFQ names the part and issue, the test codes, the severities and durations, the pass criteria and the traceability you expect for samples.
That is why we work as an ISO 9001 certified manufacturer with traceable production and documented export compliance, and why we support programmes from prototype through to volume. Test samples and production parts should come from the same controlled process, so the evidence you gather still applies on the day you deliver.
— Alexandra
A practical RFQ checklist for glass
- State the standard, part, issue number and date.
- List the test codes and tailored severities from your derived programme.
- Define pass and fail criteria: no cracking, optical performance, coating adhesion, sealing.
- Specify glass type, thickness, tolerances, edge finish and coatings.
- Request batch-level traceability for samples and production lots.
- Confirm the laboratory’s UKAS schedule covers each test and issue.
- Agree how many samples are needed for development, qualification and spares.
Custom glass for defence programmes
If you are preparing a defence build, we manufacture custom glass components such as optical windows, display glass, sensor windows, protective and chemically strengthened glass, and coated glass with AR and AG options. Browse our glass services or send us your drawing and environmental profile through Precision Glasses, and we will review manufacturability before testing begins.
FAQ
Is DEF STAN 00-35 the same as DEF STAN 00-035?
Yes. The standard was renumbered to the three-digit form, and both names refer to the Environmental Handbook for Defence Materiel. Older contracts and laboratory schedules still use 00-35, so check which issue is meant.
Which part contains the test methods?
Part 3, Environmental Test Methods. It is currently at Issue 7, published in March 2025. Parts 1 and 2 cover management and trial derivation, which you need to justify which Part 3 tests you run.
Do I need a UKAS-accredited laboratory?
For results to be accepted in formal defence qualification, yes in practice. Choose a laboratory accredited to ISO/IEC 17025:2017 and confirm its schedule lists the issue and test codes you need. Your customer’s design authority has the final say on acceptance.
Should I apply the most severe test levels to be safe?
No. The standard expects you to tailor severities to the documented service life. Unjustified severe levels raise cost and can damage equipment that would perform well in real use.
Sources
- MODUK DEF STAN 00-035 Part 3, Issue 7 listing (Accuris)
- DEFSTAN 00-035 Part 3 Issue 7 (Intertek Inform)
- DEF STAN 00-35 Part 2 Issue 4
- DEF STAN 00-35 Part 3 Issue 3
- UKAS schedule 0503
- UKAS schedule 31737
- UKAS schedule 0332
- Contracts Finder notice attachment
- Element defence testing
