Every test SELA performs follows a quality system aligned with ISO/IEC 17025:2017, the international standard for the competence of testing and calibration laboratories. It is what makes a result traceable, repeatable and defensible. SELA is working towards formal accreditation; until then, every report states the test method used and the procedures it was performed under.
Quality system: aligned with ISO/IEC 17025:2017 | Test methods: ASTM · AASHTO · BS EN · ISO · APHA | Accreditation: SELA is working towards it
What ISO/IEC 17025 requires, and how we apply it
| Requirement | What it means at SELA |
|---|---|
| Impartiality and confidentiality | We report what the tests show, whoever pays for them. Client data and results are confidential and released only to the client or with their permission. |
| Competent personnel | Each test is performed by staff trained and authorised for that method, and competence records are kept for every technician. |
| Calibrated equipment and traceability | Balances, ovens, load frames, compression machines, sieves and thermometers are calibrated on a schedule, with measurements traceable to national or international standards. |
| Standard test methods | We use published methods (ASTM, AASHTO, BS EN, ISO, APHA) and verify that we can perform each method correctly before using it for client work. |
| Sampling and sample handling | Samples are taken to an agreed sampling plan, given a unique number and tracked under chain of custody from site to final report. |
| Ensuring valid results | Routine checks include duplicate tests, reference materials and equipment checks, with inter-laboratory comparisons and proficiency testing as our programme develops. |
| Measurement uncertainty | Where a method or client requires it, we estimate and report the uncertainty of the result. |
| Reporting | Reports state the method, sample details, results and any deviation from the method, and are checked and signed by an authorised engineer. |
| Nonconforming work and complaints | Errors and deviations are recorded, investigated and corrected; complaints follow a documented process. |
| Documents, audits and review | Procedures are controlled documents, checked through internal audits and management review. |
How a sample moves through the laboratory
- Request and review: we confirm the tests, standards, acceptance criteria and deadline with the client before work starts.
- Sampling plan: locations, depths and testing frequency are agreed and recorded.
- Sampling and labelling: each sample receives a unique ID, a description and a chain-of-custody form.
- Receipt and registration: samples are checked, logged and stored under controlled conditions.
- Testing: performed to the stated method on calibrated equipment, with raw data recorded at the time of testing.
- Checking: results are compared against quality-control limits and reviewed by a second person.
- Reporting: an authorised engineer signs the report before results are released to the client.
- Retention: samples and records are kept for an agreed period so results can be re-examined.
Procedures in each laboratory
Environmental, GIS & Urban Resilience Laboratory
Environmental results depend on how samples are collected and preserved as much as on how they are analysed, so our procedures start in the field.
Key test methods
- Water sampling and analysis to ISO 5667 and APHA Standard Methods
- Soil and sediment sampling to ISO 10381 and US EPA methods
- Air quality, dust and noise monitoring to ISO and US EPA methods, including ISO 1996 for noise
- Drone mapping accuracy to ASPRS standards and geospatial data to OGC standards
Quality controls in this laboratory
- Preservation and holding times observed from site to laboratory
- Field blanks and duplicate samples on every monitoring round
- Field meters calibrated and checked before each use
- Ground control points and accuracy checks for every drone survey, and metadata recorded for every GIS dataset
See every test in this laboratory →
Geotechnical & Soil Investigation Laboratory
Soil properties vary from metre to metre, so we document exactly where, how deep and how each sample was taken, and protect its moisture until it is tested.
Key test methods
- Borehole logging to BS 5930 and Standard Penetration Tests to ASTM D1586
- Classification: grading (ASTM D6913, D7928), Atterberg limits (ASTM D4318), moisture content and specific gravity (ASTM D2216, D854)
- Compaction (ASTM D698, D1557), CBR (ASTM D1883, AASHTO T193) and field density (ASTM D1556, D6938)
- Shear strength (ASTM D2850, D3080) and consolidation (ASTM D2435)
Quality controls in this laboratory
- Drying ovens checked to hold the method temperature of 110 ± 5 °C
- Sieves inspected and verified, and compaction rammers and moulds checked for mass and dimensions
- CBR load rings and proving rings calibrated
- Samples sealed on site to preserve natural moisture content
See every test in this laboratory →
Building Materials Testing Laboratory
Concrete and steel results decide whether a structure can carry its design loads, so every specimen is identified from casting or delivery to the moment it is tested.
Key test methods
- Concrete sampling, slump and compressive strength to BS EN 12350, BS EN 12390, ASTM C143 and ASTM C39
- Cement to BS EN 196 and ASTM C150, and non-destructive testing to BS EN 12504 and ASTM C805
- Reinforcing steel to BS EN ISO 6892, BS 4449, ASTM A615 and ASTM A370
- Masonry and blocks to ASTM C140 and BS EN 772
Quality controls in this laboratory
- Compression and tensile testing machines verified for force accuracy
- Curing tanks held at the method temperature of 20 ± 2 °C
- Cube moulds checked for dimensions and flatness
- Failure mode recorded for every crushed specimen
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Transport & Pavement Laboratory
Bitumen and asphalt properties change with temperature, so temperature control and records run through every procedure in this laboratory.
Key test methods
- Aggregates to BS 812, ASTM C131 (AASHTO T96), ASTM C136 and ASTM C88
- Bitumen penetration, softening point, ductility and viscosity to ASTM D5, D36, D113 and D2170
- Asphalt Marshall stability and flow (ASTM D6927), binder content (ASTM D2172) and core density (ASTM D2726)
- Pavement layer design to AASHTO and TRL methods
Quality controls in this laboratory
- Water baths and ovens temperature-controlled and logged, including the 25 °C bath for penetration tests
- Marshall compaction hammers and breaking heads checked
- Duplicate tests on bitumen samples
- Asphalt temperature recorded at mixing and compaction, and field density checked against the approved job mix
See every test in this laboratory →
Our road to accreditation
SELA’s Advanced Engineering Laboratory Complex in Marshall City is designed to bring these procedures under one roof. We are building the records, staff competence and proficiency history that formal ISO/IEC 17025 accreditation requires, and we will announce each milestone on our blog.
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OUR ROADMAP
The road to accreditation
SELA is building toward formal ISO/IEC 17025:2017 accreditation through a recognised accreditation body. The process is rigorous and deliberate — every step builds the quality system that will earn and sustain the accreditation our clients require.
Phase 1 · Foundation
Quality system design
- Quality manual and management system documentation
- Standard operating procedures for every test method
- Document control and records management system
- Staff competence framework and training plans
- Equipment calibration schedules and traceability
Status: Under way — quality manual and SOPs in development
Phase 2 · Implementation
System in operation
- Laboratory commissioned with calibrated equipment
- LIMS deployed for sample tracking and reporting
- Method validation and verification complete
- Internal audits and management review cycles running
- Proficiency testing programme enrolled
Status: Planned — begins with laboratory commissioning
Phase 3 · Pre-assessment
Readiness review
- Gap analysis against ISO/IEC 17025:2017 clauses
- Corrective actions on any findings
- Pre-assessment visit by the accreditation body
- Full system documentation reviewed and finalised
Status: Planned — follows 6+ months of system operation
Phase 4 · Accreditation
Formal assessment
- Application submitted to SANAS, GhaNAS or equivalent body
- On-site assessment by accreditation assessors
- Resolution of any non-conformances raised
- Accreditation certificate granted for approved scope
- Ongoing surveillance audits to maintain accreditation
Target: 12–18 months after laboratory launch
Why accreditation matters: ISO/IEC 17025 accreditation is the internationally recognised standard for testing laboratories. It is a strict requirement on World Bank, AfDB, EU, and MCC-funded infrastructure projects — and a mark of trust for every client. SELA is building every system with accreditation as the goal from day one.