Ex Equipment Technical Bid Evaluation Checklist: A 25-Point TBE Review
Technical Bid Evaluation (TBE): checking Ex equipment against project requirements, certification, hazardous area classification, and technical compliance.
Technical bid evaluation is one of the most important stages in the procurement of electrical equipment for hazardous areas. A vendor offer may appear compliant at first glance, but important differences can exist in certification, hazardous area suitability, temperature class, equipment protection level, ambient temperature, cable entries, accessories, and documentation.
A structured Technical Bid Evaluation (TBE) helps the engineering and procurement team compare the vendor offer against the actual project requirements instead of evaluating equipment only by model number, price, or general Ex certification.
This article provides a practical 25-point checklist for evaluating Ex electrical equipment before commercial evaluation and purchase order placement.
What Should a Technical Bid Evaluation Check?
The purpose of a TBE is not simply to determine whether a product is Ex certified. The evaluation should establish whether the exact equipment and configuration offered satisfy the complete technical requirements.
IEC 60079-14 addresses electrical installation design, equipment selection and installation, initial inspection, documentation, and personnel competency within its scope. A TBE supports this process by connecting the project requirements with the offered equipment, certification, configuration, and installation requirements.
25-Point Ex Equipment TBE Checklist
Use the following checklist to compare the vendor's offer against the RFQ, project datasheet, equipment schedule, and applicable project specifications.
| # | Check Item | What to Verify |
|---|---|---|
| 1 | Equipment Type | Confirm that the offered equipment performs the function required by the RFQ, datasheet, or equipment schedule. |
| 2 | Manufacturer and Model | Record the exact manufacturer, product family, model number, and configuration offered. |
| 3 | Hazardous Area Classification | Check suitability for the applicable Zone or other hazardous area classification specified for the installation. |
| 4 | Equipment Protection Level (EPL) | Verify that the offered EPL is suitable for the required hazardous area and application. |
| 5 | Ex Protection Type | Confirm the required protection concept, such as Ex d, Ex e, Ex i, Ex p, Ex ec, Ex t, or another applicable type. |
| 6 | Gas or Dust Group | Verify the applicable gas group or dust group against the hazardous substance and project requirements. |
| 7 | Temperature Class | Check that the temperature class or maximum surface temperature meets the project requirements and hazardous substance limitations. |
| 8 | Ambient Temperature | Compare the certified or specified ambient temperature range with the actual project environmental requirements. |
| 9 | Ingress Protection | Verify the IP rating against the environmental and installation requirements. |
| 10 | Electrical Rating | Check voltage, frequency, current, power, phase, and other applicable electrical characteristics. |
| 11 | Performance Requirements | Verify application-specific performance, such as lumen output, operating capacity, communication capability, or load rating. |
| 12 | Material of Construction | Check the enclosure, body, lens, gasket, mounting material, and other materials against environmental and project requirements. |
| 13 | Cable Entries | Verify entry type, thread size, quantity, material, certification requirements, and compatibility with the installation. |
| 14 | Cable Glands | Confirm whether glands are included and whether their type, certification, and specification suit the equipment and cable construction. |
| 15 | Plugs and Accessories | Check blanking plugs, reducers, adaptors, brackets, mounting hardware, guards, visors, and other required accessories. |
| 16 | Ex Certificate | Verify the applicable certificate and confirm that it corresponds to the equipment type and protection concept offered. |
| 17 | Certificate Conditions | Review special conditions of use, limitations, certificate suffixes, variants, and associated documentation where applicable. |
| 18 | Ex Marking | Compare the marking against the required equipment group, protection type, gas or dust group, temperature class, and EPL. |
| 19 | Product Configuration | Confirm that the certified configuration corresponds to the actual offer, including options and accessories where relevant. |
| 20 | Vendor Datasheet | Compare the vendor datasheet line by line with the project datasheet and RFQ requirements. |
| 21 | Technical Deviations | Identify and record every deviation. Do not assume that an unmentioned requirement is compliant. |
| 22 | Installation Requirements | Check mounting orientation, cable entry arrangement, earthing, clearances, environmental conditions, and other installation constraints. |
| 23 | Documentation | Confirm the availability of datasheets, certificates, manuals, drawings, schedules, declarations, and other required documents. |
| 24 | Inspection and Testing | Identify required inspections, tests, certificates, routine test records, and project-specific documentation before shipment or installation. |
| 25 | Final Compliance Status | Assign a clear status—Comply, Deviation, Clarification Required, or Not Comply—based on documented evidence. |
Do Not Evaluate the Offer From the Ex Certificate Alone
One common evaluation error is treating the existence of an IECEx or other Ex certificate as proof that the complete vendor offer satisfies the project requirements.
Certification is essential where required, but it does not eliminate the need to check the exact model, configuration, environmental limits, electrical ratings, performance, cable entries, accessories, and installation requirements.
For example, a certificate may cover a particular protection concept and temperature class, while the project also requires an ambient temperature range of -40°C to +60°C, a specific cable entry arrangement, or a minimum lighting output. These requirements must be assessed separately.
A Practical TBE Comparison Matrix
Place the project requirement and vendor offer side by side. Record the supporting document and explain any difference instead of relying on a general statement of compliance.
| Requirement | Project Requirement | Vendor Offer | Status | Remarks |
|---|---|---|---|---|
| Hazardous Area | Zone 1 | Zone 1 | Comply | Confirm from applicable technical documents. |
| Gas Group | IIC | IIC | Comply | Check against the applicable certificate and marking. |
| EPL | Gb | Gb | Comply | Confirm that the protection level is suitable for the application. |
| Temperature Class | T4 | T4 | Comply | Verify the actual offered configuration. |
| Ambient Temperature | -40°C to +60°C | -20°C to +60°C | Deviation | Vendor clarification or a suitable alternative is required. |
| Ingress Protection | IP66 | IP66 | Comply | Confirm from product documentation. |
| Cable Entry | Specified arrangement | Alternative proposed | Clarification Required | Check compatibility, installation requirements, and certification conditions. |
The entries above are illustrative examples, not approval of any specific equipment.
Why Vendor Deviations Should Be Recorded Clearly
A technical deviation should not disappear inside a vendor quotation. Recording it in the TBE creates a traceable record of what was offered, what differs from the project requirements, and what remains unresolved.
For example:
Vendor proposes an ambient temperature range of -20°C to +60°C against the project requirement of -40°C to +60°C. Vendor to confirm suitability for the specified operating conditions or propose an alternative configuration with supporting technical documentation.
This makes the technical gap visible to engineering, procurement, and the vendor before the commercial decision is finalized.
Comply, Deviation, Clarification Required, or Not Comply?
- Comply: The documented offer satisfies the stated requirement.
- Deviation: The documented offer differs from the stated requirement. The deviation must be recorded and assessed.
- Clarification Required: The available information is insufficient to establish compliance.
- Not Comply: The documented offer fails a mandatory technical requirement, subject to the project's evaluation procedure.
Use the project's approved TBE procedure for handling deviations, mandatory requirements, and technical clarifications. Do not mark an item as compliant simply because the vendor has not identified a deviation.
Five Documents to Cross-Check During TBE
A sound evaluation should cross-check relevant information across multiple documents rather than relying on a single vendor submission.
- Project datasheet or equipment specification
- Vendor technical datasheet
- Ex certificate and associated certification documentation
- Vendor technical offer and deviation list
- Installation requirements and project drawings, where applicable
Look for inconsistencies between these documents. The model number in the quotation should correspond with the datasheet and certified equipment configuration. Separately quoted accessories should also be checked against the required configuration and installation arrangement.
Example: How One Small Deviation Can Affect the Evaluation
Consider an illustrative outdoor Ex luminaire requirement:
- Hazardous area: Zone 1
- Gas group: IIC
- EPL: Gb
- Temperature class: T4
- Ambient temperature: -40°C to +60°C
- Minimum light output: 12,000 lm
- Ingress protection: IP66
- Electrical supply: 230 V AC, 50 Hz
Assume a vendor proposes a luminaire meeting the stated Zone, gas group, EPL, temperature class, IP rating, voltage, and light output requirements, but its documented ambient range is only -20°C to +60°C.
The offer should not be marked fully compliant just because the equipment has the correct Ex certification. The ambient temperature requirement is a separate criterion. Record the difference as a deviation or clarification item until the proposed configuration's suitability is established.
TBE Review Sequence
- Read the RFQ, project datasheet, and applicable specifications.
- Identify the hazardous area classification and required equipment suitability.
- Check EPL, protection type, gas or dust group, and temperature requirements.
- Confirm the exact manufacturer, model, and offered configuration.
- Review the applicable Ex certificate and its conditions.
- Compare electrical ratings, environmental limits, and performance.
- Review cable entries, glands, accessories, and installation requirements.
- Cross-check the supporting documents.
- Record deviations and request clarification where evidence is incomplete.
- Finalize the TBE with a traceable status and supporting remarks for each requirement.
What a Good TBE Should Leave Behind
The final TBE should allow another engineer to understand why an offer was considered compliant, which deviations were identified, what clarifications were obtained, and which items remain unresolved.
A well-documented TBE becomes part of the project's technical decision record. It supports procurement decisions and provides a reference for subsequent document review, inspection, and installation activities.
Related Reading
- Ex Equipment Selection Best Practices Before Procurement
- How to Review an Ex Equipment Datasheet Before Procurement
- Ex Equipment Selection Case Study: From Hazardous Area Classification to Final Procurement
- IEC 60079-14 Explained
- How to Verify an IECEx Certificate
- Equipment Protection Level (EPL) Explained
- Temperature Classes T1–T6 Explained
- Gas Groups IIA vs IIB vs IIC
- Zone 0 vs Zone 1 vs Zone 2
References
- IEC 60079-14:2024 — Explosive atmospheres — Part 14: Electrical installation design, selection and installation of equipment, including initial inspection.
- IEC 60079 series — Explosive atmospheres.
About ExProofHub: ExProofHub provides practical technical reference material for engineers, consultants, EPC professionals, procurement teams, and other practitioners working with explosion-protected equipment and hazardous-area installations.
Join the conversation