Today’s situation

In injection and extrusion moulding, the most common and most dangerous nonconformity is working with guards switched off. Being caught in the clamping unit of an injection moulding machine always comes out as "high" in the industry’s risk assessments, yet for short jobs such as adjusting a mould or removing foreign matter, a habit of bypassing the safety-gate interlock "because it only takes a moment" forms easily. Once a company grows past 100 people, machines and shifts multiply, managers cannot see every machine every day, and checklists often carry nothing but "no problems" marks. ISO 45001 requires risk assessment, operational control and worker participation, and working with a guard bypassed may breach occupational safety and health legislation (check the detailed provisions of the law).

About the company (fictional)

• Company N is a plastic injection moulder making automotive interior parts and appliance housings. About 180 people (example), two shifts.
• It runs 42 injection moulding machines, 6 granulators and a mould maintenance room (example).
• It holds ISO 9001 and ISO 14001 certification and, at a customer’s request, is building an ISO 45001 system (example).

What happened

While the night-shift leader was removing foreign matter from a mould, a co-worker pressed the cycle start button and the clamping unit began to close. Fortunately the night-shift leader pulled their hand out in time and was not hurt, and the event was reported as a near miss.

When the Health and Safety Team Leader checked the site, the safety-gate interlock on that machine had been bypassed with a bypass key. A check of all machines then found the same condition on 5 of the 42 machines (example). The daily checklist had been marked "interlock normal" every day.

• From the ISO 45001 point of view: the risk-reduction measure set in the risk assessment (the safety-gate interlock) was not maintained in operational control, and the inspection records did not match reality (check the clauses).
• From the legal point of view: working with a guard bypassed may breach occupational safety and health legislation, and the company also had to check whether its injection moulding machines are machinery subject to statutory safety inspection and what their inspection history was (check the law).

Causes

1. Production pressure and habit — because closing the safety gate during mould adjustment delays the restart, using the bypass key had become a habit among the shift leaders.
2. No bypass and restore procedure — there was no documented information setting out when a guard may be bypassed, who authorizes it, lockout and tagging, and confirmation of restoration, and the checklist had only a "checked" box, so what was actually to be looked at was not defined.
3. The risk assessment had stood still — after the assessment two years earlier, no ad hoc assessment was made when machines were added or new moulds were brought in, and there was no record of shop-floor workers taking part in the assessment and in deciding the measures.

How eiso was used to fix it

1. Immediate action — the 5 machines (example) were stopped and their interlocks restored, and all bypass keys were collected and placed in the keeping of the Health and Safety team.
2. Information gathering — the team asked Find ISO Reference Materials about "controlling guard bypass on injection moulding machines" and used the safety inspection forms and risk assessment materials found in the Information Collection library as a starting point.
3. Writing the guideline — in Individual Document Development, "Document type" was set to Guidelines and the document name to "Guard control guideline", with the existing daily checklist placed in "Related materials". The draft received covered the jobs for which bypass is allowed, the authorizer, lockout and tagging, a signature confirming restoration, and the items to actually check on the checklist (testing that the clamping unit does not move with the gate open). The Health and Safety team adapted it to the shop floor and the plant manager approved it.
4. Redoing the risk assessment — in Management System Documentation, the team chose ISO 45001 and "Draft risk and hazard assessment table" and reassessed being caught in the clamping unit, mould changes and the granulator feed opening. Criteria were added for ad hoc assessment when machines are added, new moulds are brought in or processes change, and shift leaders and worker representatives took part in the assessment meeting and recorded their views.
5. Shop-floor training — with Training Materials and Lesson Plans, a 30-minute PPT "Why guards must never be switched off" was made and delivered to both shifts, and workers’ comments after the training were reflected in the guideline.
6. Checking effectiveness — the company decided to check for bypassing for 3 months through weekly unannounced inspections and internal audit.

Results and preventing recurrence

• Unannounced inspections found 0 interlock bypasses (example), and by changing the order of the cycle restart, waiting time for mould adjustment fell by 2 minutes per adjustment on average (example).
• Near-miss reports actually rose (from 3 to 9 a month, example). The company sees this as a sign of a culture of reporting rather than hiding.
• The risk assessment sheet, guideline and training records were brought together as documented information and included in the management review inputs.

Check your own company

• Can you be sure there is not a single bypass key or disabled limit switch on your shop floor right now?
• Are the cases in which a guard may be bypassed, the authorizer and confirmation of restoration set out in documented information?
• Does your daily checklist state how to actually test, rather than just carry a "checked" mark?
• Do you redo the risk assessment when you add machines or bring in new moulds?
• Do you have records of shift leaders and workers taking part in the risk assessment and in deciding measures?
• Have you checked whether equipment such as injection moulding machines and granulators is subject to statutory safety inspection (check the law)?

See also

• Individual Document Development
• Management System Documentation
• Find ISO Reference Materials Example
• eiso Pricing