Heating Rate Controller · RA-R1.1 · 26 October 2026
Equipment risk assessment
Two-channel 230 V AC controller, shared 24 V DC logic and independent externally supplied 0–60 V / 15 A heater channels.
Scope, users and status
Applies to preparation, routine supervised heating, shutdown, cleaning, and permitted maintenance of the laboratory heating-rate controller. Intended users: trained test operators, responsible electrical engineer, site safety team and authorised maintenance technicians.
Assessment status: draft — site review and approval required before live testing. Functional operation does not establish independent electrical safety approval, fail-safe output behavior, over-temperature protection or suitability for every specimen. Risk controls below must be implemented and signed off locally. This document is not a certification.
Experiment-specific hazards: heating a battery, reactive material, pressurised vessel or combustible assembly can cause a hazard even after power is removed. A separate specimen/process assessment must define containment, ventilation/extraction, remote operation, fire and emergency procedures before the test. This equipment assessment does not authorise thermal-runaway or destructive tests by itself.
Risk scoring · 5 × 5 working matrix
Score Likelihood (L) and Severity (S) from 1 to 5. Calculate Risk (R) = L × S. Score once for the initial risk and again after additional controls have been implemented and verified. Use the site-approved definitions and acceptance limits if different.
| 1 | Rare |
|---|---|
| 2 | Unlikely |
| 3 | Possible |
| 4 | Likely |
| 5 | Almost certain |
| 1 | Negligible / no injury |
|---|---|
| 2 | Minor injury |
| 3 | Moderate injury / significant loss |
| 4 | Major injury / serious loss |
| 5 | Fatality or catastrophic loss |
Example of calculation
L = 3 and S = 4 gives R = 12.
Risk acceptability, escalation and required sign-off follow the site's own safety rules. No numerical risk score implies that equipment is approved.
The existing-control column records design features and stated arrangements, not a claim that their inspection is complete. The action column is deliberately kept separate. Complete action ownership, due date, evidence and assessment approval before using this document as a signed RA.
Risk assessment register
18 hazards · standard before/after scoring with likelihood (L), severity (S) and risk rating (R = L × S)
0 / 18 residual risks scored
| Ref. | Hazard and potential harm | Persons at risk | Existing / designed controls (verify status) | Initial risk | Further control measures / actions required | Residual risk | Action owner / due / status |
|---|---|---|---|---|---|---|---|
| L × S = R | L × S = R | ||||||
| RA-01 | 230 V AC inside controller Potential harm: Electric shock, arc, burns, fire |
Operator, maintenance staff | Enclosed metal cabinet; fused/switched Schurter mains inlet; PE bonding included in R1 electrical design. Status: design / stated arrangement; verify on equipment |
R— |
Competent inspector to check PE continuity (door and cabinet), insulation, bonding, protective-device coordination and lock-off/prove-dead method. Record acceptance. Evidence: Mains/PE test record and isolation procedure |
R— |
Competent electrical inspector Target: Before first use; after rewiring Status / closed: __________ |
| RA-02 | External DC 0–60 V / up to 15 A per channel Potential harm: DC short circuit, arcing, hot conductors, burns and possible shock |
Operator, technician | Separate external DC source for each channel; Lovato DC breaker and Electro PJP panel connectors specified in R1. Status: design / stated arrangement; verify on equipment |
R— |
Check external PSU fault energy; approve cable, connectors, DC breaker interruption rating and accessible DC isolation. Verify wiring/polarity, secure strain relief and test disconnect. Evidence: Protection coordination + disconnect test |
R— |
Electrical responsible person Target: Before first use and each configuration change Status / closed: __________ |
| RA-03 | Hot heater and fixture / residual heat Potential harm: Contact burns, ignition of nearby objects |
Operator, visitors | Heater and fixture are external test items. The controller itself provides no physical guard or assured cooldown interlock. Status: design / stated arrangement; verify on equipment |
R— |
Fit guarding or exclusion barrier, thermal warning labels and suitable heatproof working surface. Define safe-touch temperature and cooling confirmation. Evidence: Guard and cooling checklist |
R— |
Test operator Target: Each test Status / closed: __________ |
| RA-04 | Excess temperature or uncontrolled heating Potential harm: Fire, damage to equipment/specimen; severe thermal event |
Operator, building occupants | Omron Type K feedback, Finder mechanical contact and Crydom SSR provide regulation and commanded switching only. Status: design / stated arrangement; verify on equipment |
R— |
Set verified controller limits and fault behaviour. Add independent, suitable over-temperature protection where foreseeable consequences require it; verify fault response with the actual load. Evidence: Independent limit/protection verification |
R— |
Responsible engineer + site safety Target: Before routine service Status / closed: __________ |
| RA-05 | Thermocouple failure, misplacement or wrong type Potential harm: Incorrect PV, runaway, damage, burn |
Operator; specimen | Omron E5CC-T accepts an external Type K thermocouple through dedicated panel input. Status: design / stated arrangement; verify on equipment |
R— |
Secure sensor in representative position, inspect Type K polarity/extension lead, check measured PV independently, and prove response to sensor fault. Evidence: Sensor check and fault response |
R— |
Operator Target: Each test Status / closed: __________ |
| RA-06 | Wrong programme, rate, ramp or end action Potential harm: Unexpected fast heating, extra soak, over-temperature |
Operator, test specimen | Stored Omron programmes and separate heater-enable circuit allow programme selection before energising. Status: design / stated arrangement; verify on equipment |
R— |
Review approved prg, ramp rate, peak, soak, repeats and end action against test sheet. Record start condition and start one channel at a time unless authorised otherwise. Evidence: Signed test-specific programme sheet |
R— |
Operator / reviewer Target: Each test Status / closed: __________ |
| RA-07 | Controller RESET / output not inactive Potential harm: Heater energises when channel ENABLE turned on |
Operator, specimen | Omron RUN/RESET is separate from EAO heater-enable control, but RESET output-off behaviour is not independently proven. Status: design / stated arrangement; verify on equipment |
R— |
Document rtsm / p-on / mv-r settings. Prove SSR input and heater demand are OFF in RESET and on sensor fault using suitable test methods before applying the SOP start order. Evidence: RESET output-off functional test |
R— |
Competent commissioning engineer Target: Prior to SOP start order Status / closed: __________ |
| RA-08 | Mismatched ENABLE / ACTIVE indication Potential harm: Unexpected heater operation or false reassurance |
Operator | The reference circuit supplies ACTIVE LED+ from Finder 13.61 terminal 14 through EN1/EN2, and returns LED− through its Weidmüller demand-controlled path. Status: design / stated arrangement; verify on equipment |
R— |
Verify HL+ comes from the correct Finder 13.61 terminal 14 (EN) and HL− remains on the Weidmüller-controlled return for BOTH channels. Check terminal-conductor capacity and test ENABLE OFF / demand ON, ENABLE ON / demand OFF, and ENABLE ON / demand ON; record results. Evidence: Indicator truth-table check |
R— |
Electrical maintainer Target: Before relying on indicators Status / closed: __________ |
| RA-09 | Loss and restoration of mains or DC supply Potential harm: Unexpected restart, uncontrolled heat or invalid profile |
Operator, specimen | Finder 13.61 step relay used for channel enable; Omron offers configurable startup behaviour. Status: design / stated arrangement; verify on equipment |
R— |
Test mains/DC loss and restoration: Finder enable must stay OFF, Omron returns to RESET, and heater cannot restart without a deliberate operator action. Abort interrupted tests. Evidence: Power cycle/restart test record |
R— |
Competent engineer / operator Target: Commissioning, then periodic functional checks Status / closed: __________ |
| RA-10 | DC relay/socket/SSR overload or polarity Potential harm: Contact overheating, welded contacts, fire, loss of isolation |
Operator, facility | R1 specifies Finder 62.31 34(+)→14(−), Crydom DC SSR and Lovato breaker. Protection coordination is not signed off. Status: design / stated arrangement; verify on equipment |
R— |
Check 62.31 contact polarity, actual socket rating at 15 A, coil drive, Crydom thermal derating/spacing, conductor size and DC overcurrent protection. Document duty thermal test. Evidence: Thermal test and manufacturer rating check |
R— |
Competent design reviewer Target: Before prolonged 15 A tests Status / closed: __________ |
| RA-11 | Voltage meter branch insufficiently protected Potential harm: Wiring fault, overheating or fire |
Operator, facility | PV1 and PV2 have no external input-wire fuses fitted, confirmed for the completed equipment. Murata requires 0.25 A / 300 V time-delay protection for the TB1 (+) and (−) input supply wiring; the internal self-resetting device does not protect the upstream leads. A supply-wire fault could cause overheating or fire. Status: confirmed protection discrepancy — OPEN; not approved for live heating. Corrective action and evidence record |
R— |
Resolve the external TB1 (+/−) input-wire protection on both meters to the Murata 0.25 A / 300 V time-delay specification. Choose fuse/holder configuration and DC interrupt capability for the actual supply and earthing topology; verify installation, polarity, ratings and protection. Record the competent electrical inspection before release; internal meter fusing is not a substitute. Evidence: Meter branch protection drawing + inspection |
R— |
Electrical designer Target: Before revised rebuild/use as applicable Status / closed: __________ |
| RA-12 | Wrong channel, swapped PSU/heater connections Potential harm: Unexpected heat, polarity damage, energising wrong fixture |
Operator, specimen | Two independent channel circuits, colour-coded DC connectors, and separate PSU IN / HEATER OUT panel connector markings (confirm actual fitted labels). Status: design / stated arrangement; verify on equipment |
R— |
Fit permanent labels; check upper PSU IN/lower HEATER OUT per channel; independently check each socket, polarity and lead route without supply energised. Evidence: Channel cross-check |
R— |
Operator plus checker Target: Each set-up Status / closed: __________ |
| RA-13 | Specimen-related reaction or emissions Potential harm: Fire, fumes, venting, explosion or pressure release depending on specimen |
Operators, visitors, facility | Controller is a heat source only; specimen chemistry, failure behaviour and test-cell controls vary by experiment. Status: design / stated arrangement; verify on equipment |
R— |
Create and approve specimen-specific RA for battery/chemical/pressurised/combustible hazards, containment, ventilation, remote operation, fire response and safe exclusion zone. Evidence: Approved specimen-specific risk assessment |
R— |
Experiment owner / H&S Target: Each test programme and new sample type Status / closed: __________ |
| RA-14 | Loss of cooling, ventilation or monitoring Potential harm: Overheating after heater stopped, fumes or fire |
Operator, specimen | Heating process depends on external cooling, extraction and supervision; controller has no proven cooling interlock. Status: design / stated arrangement; verify on equipment |
R— |
Check cooling and extraction before starting, monitor independent temperature, define ventilation-failure stop actions and supervise cooldown. Evidence: Cooling/ventilation functional check |
R— |
Operator Target: Each test Status / closed: __________ |
| RA-15 | Emergency response, isolation not accessible Potential harm: Delayed power removal, increased injury |
Operator, bystanders | External DC PSU and mains inlet can be switched off, but EAO is an operating enable, not safety-rated emergency stop. Status: design / stated arrangement; verify on equipment |
R— |
Identify/test rated external DC isolator and safe-to-reach AC disconnect; train operators in alarm and evacuation response without approaching faulted apparatus. Evidence: Emergency drill / isolation sign-off |
R— |
Facility owner / safety lead Target: Before first use Status / closed: __________ |
| RA-16 | Maintenance on energised equipment Potential harm: Shock, arc, accidental energisation |
Electrician/technician | Separate mains supply and external DC heater sources; cabinet can remain energised from either. Status: design / stated arrangement; verify on equipment |
R— |
Competent maintenance staff only. Isolate and secure BOTH mains and external DC sources, allow for stored energy, verify dead before touching, and document reinspection. Evidence: Permit / lock-off record |
R— |
Maintenance lead Target: Every intervention Status / closed: __________ |
| RA-17 | Cable routing, leads crossing hinges / trip hazard Potential harm: Abrasion, short, strain, trip, burns |
Operator, staff | Panel-mounted DC connectors, enclosure hinge and routed test leads require mechanical protection. Status: design / stated arrangement; verify on equipment |
R— |
Secure cables and terminals; protect hinge-crossing loom, avoid heater/hot/abrasive edges, inspect banana retention and keep routes clear. Evidence: Cable/clearance inspection |
R— |
Operator / electrical reviewer Target: Initial installation and each visual check Status / closed: __________ |
| RA-18 | Multiple channels loaded simultaneously Potential harm: Combined heat load, shared 24 V failure, mistaken cross-channel actions |
Operator, facility | Each heater channel has a separate DC path and controller; the Mean Well 24 V logic supply is shared. Status: design / stated arrangement; verify on equipment |
R— |
Assess combined specimen heat release, cooling/extraction, DC supply duty, operator attention and fault response; explicitly approve simultaneous heating if allowed. Evidence: Two-channel capability approval |
R— |
Experiment owner Target: Before two-channel runs Status / closed: __________ |
Initial risk: before completing the further measures. Residual risk: after controls are implemented and verified. Neither is pre-scored; the responsible site assessor must complete both. Values selected on this page are for this browser session only; Print / Save PDF to retain the completed assessment.
Guidance: HSE risk assessment principles ↗. The scoring system below is a working template; follow the site-approved matrix and acceptance criteria where these differ.
Evidence required before routine live tests
The following are practical release checks, not a statement that they have been passed.
- □ Electrical inspection: mains/PE bonding, insulation, approved circuit protection, cable ratings and accessible independent DC isolation.
- □ Verify Omron r-r RESET really removes demand on both channels (rtsm=stop, mv-r=0%, sensor fault response).
- □ Power-restoration test: both channel enable outputs OFF; Omron starts in RESET; no automatic heating.
- □ Verify independent over-temperature, ventilation/containment, and test-specific measures for the intended specimen.
- □ Confirm 62.31 and socket suitability at actual DC current/duty, Crydom heat dissipation and the unresolved Murata external input-wire protection.
- □ Verify both channels: CONTROL selector, EAO toggle, EN ring, amber ACTIVE gated by EN + demand, output switching and safe shutdown.
Do not rely on EAO heater enable as a safety-rated emergency stop. Site emergency isolation must act on the relevant independent energy source, without requiring the operator to approach a hot or faulted test.
Record for each experiment
- □ Test identifier, operator(s), specimen, fixture and specimen-specific hazard assessment.
- □ Channel(s), selected programme number, ramp/peak/soak, control limits, planned endpoint and sample temperature limit.
- □ External PSU model, maximum voltage and current-limit setting, heater/cable/connector rating.
- □ Visual inspection, temperature sensor PV validation, safe isolation arrangement, independent temperature/cooling.
- □ Start/stop times; Omron segment and event record; abnormal results; sign-off and post-test cool down.
Review this assessment following alterations to wiring/components, new specimen categories, any unexpected heating or faults, an incident or near miss, or changes to the work area/protective equipment.
Review and authorisation
Risk scoring, adequacy and effectiveness of controls, responsible persons, due dates and sign-off must be completed by competent local reviewers. Record reference to the approved site-specific specimen assessment.
Equipment / serial / location_______________________________________________
Specific test category or specimen RA number_______________________________________________
Electrical inspector / date_______________________________________________
Test owner / date_______________________________________________
H&S reviewer / date_______________________________________________
Approval / next review date_______________________________________________
References: Electrical overview, Reference Wiring R1, Operating procedure, HSE safe electrical work.