Executive TL;DR
MTE Ordinance No. 344 of March 21, 2024, published in the Official Gazette (DOU) on the same date, is not a "new technical package" of ISO 13849 categories embedded in NR-12. It amends glossaries: in NR-1, it expands definitions in Annex I — Glossary (including explicit references to international and Brazilian standards); in NR-12, it removes terms from Annex IV — Glossary (including expressions linked to "harmonized European standards" and "official/international technical standards" in the then-current wording). Entry into force occurred upon publication. Meanwhile, NR-12 continues to require protection against mechanical hazards, stop devices, risk analysis, and PGR integration — and machine engineering continues to use, as good practice, the ISO 12100 family (hazard identification and risk estimation) and ISO 13849 (safety-related control system performance) as a method to demonstrate compliance, without confusing international standards with a substitute for Brazilian legal text.
Table of contents
- What Ordinance 344/2024 actually changed
- NR-12: the legal core inspectors check on the floor
- ISO 12100 and ISO 13849: where they fit without becoming a "phantom mandate"
- Machine lifecycle: procurement, retrofit, and process change
- PGR, inventory, and machine incidents
- Internal audit checklist (minimum package)
- Typical errors in industrial plants
- FAQ
- References
What Ordinance 344/2024 actually changed
The first editorial step is to demystify: if your investment committee approved budget citing "344 change in NR-12 to put PLr on everything," reopen the official PDF. The ordinance is glossary normative and conceptual harmonization between standards in the Brazilian OHS system — useful for contracts, reports, and training, because it clarifies how MTE names technical references and roles.
In NR-1, the most cited practical gain by lawyers and consultants is the reinforcement of vocabulary on technical standards (including NBR/ABNT and ISO/IEC per the published text) and adjustments to definitions such as technical responsible party in training and qualification, per the Annex I wording after the ordinance. This cuts across all NRs: it reduces ambiguity when the PGR cites "international best practices" alongside legal obligation.
In NR-12, the exclusion of certain terms from Annex IV — Glossary pushes the debate to the regulatory text itself on machinery — guards, distances, emergency stops, control systems — instead of relying on auxiliary definitions that sometimes confused first-time auditors. The positive side effect in enterprise is standardizing opinions across factories: less semantic debate, more photo of the light curtain with date and manufacturer.
Honest reading: the ordinance does not replace ISO 13849 category specification in CLIF (logic component) design nor firmware validation. Anyone promising "344 compliance" selling only checklist software is confusing legal instrument with engineering.
NR-12: the legal core inspectors check on the floor
Machine inspection is material: fixed guarding of hazardous drives, accessible emergency stop, safe distance from crush points, interlock that does not allow involuntary restart, protection sensors with response compatible with machine stop time. In robotization, delimited cells, speed reduction in human presence, and teaching procedure when there is human-robot collaboration — always check the annex and chapter applicable to the equipment type.
NR-12 also requires a manual in Portuguese, clear identification of limitations, and maintenance that preserves safety characteristics; on import, the compliance team should treat CE or equivalent as manufacturer reference, not as a substitute for local legislation evaluation.
Integrations with other NRs arise daily: NR-10 on electrical panels and lockouts, NR-17 on pace and workstation when the machine requires incompatible biomechanical load, NR-35 on maintenance at height on large presses and filling lines. NR-12 does not live in isolation — the PGR is the map where this appears systemically.
ISO 12100 and ISO 13849: where they fit without becoming a "phantom mandate"
ISO 12100 guides hazard identification and severity and probability estimation — the skeleton of a defensible risk analysis when someone asks "why this interlock and not just a written warning?". ISO 13849-1 covers SRP/CS architecture (safety-related control system), categories, MTTFd, DCavg, and CFP to reach the PL required for each safety function — useful on presses, robots, packaging lines with monitored clutch.
The most common misunderstanding is thinking that reaching PL e or category 3 means the machine is "110% legal". In Brazil, the final parameter is NR-12 and stop test under real production conditions (including noise, dust, vibration affecting sensors). ISO standards provide an engineering path; the OHS auditor may require evidence that dangerous failure rate was considered in validation — record of proof-bar torque test, stop time recording, and versioned firmware.
For integrators building cells with safety PLCs, document LOTO (tag list), cause-and-effect diagram of the safety function, and comparison between calculated PLr and achieved PL. This becomes an ISO 45001 audit annex and defense in labor lawsuits when MPT discusses technical subordination between machine manufacturer and in-house modified machinery.
Machine lifecycle: procurement, retrofit, and process change
Procurement specification
A mature RFQ requires a safety single-line diagram, SIL/PL list per function, MES interface without neutralizing stop, and maintenance window that does not force guard disabling "just this once". Include contractual penalty for retrofit without change documentation — very common when the supplier swaps the inverter and disables dual relay input.
Process changes ("was safe until it became something else")
When a generic machine starts machining another alloy or gains feed automation, risk changes. Update Risk Analysis and operating procedure before releasing production. In audits, equipment with bypass history are probes for negligent crime in harsh discussions — SESMT must physically block ways to jump the curtain.
Retrofit and third parties
Installers of fixed guarding with improvised welding and paint over sensors have already caused shutdowns. Require ART when applicable and photo with part code in the safety storeroom.
PGR, inventory, and machine incidents
The PGR (and GRO, by company size) must register critical machines: packaging line with frequent access to roller zone, saw without recoverable two-hand sensor, press with heavy tooling. List asset owner, date of last stop validation, and reanalysis trigger (program change, nominal speed change).
Incidents with machinery often become CAT (victim follow-up) and S-2210 in eSocial when characterized as typical accident after medical and legal evaluation — the text integrates Occupational Medicine, HR, and engineering in a single narrative. Divergence between internal video and preliminary report leaves Compliance vulnerable; treat image preservation as a formal procedure, not an IT favor.
Internal audit checklist (what SESMT should find in 15 minutes)
In acquisition due diligence or inspection simulation, the minimum package per critical line includes: manufacturer declaration or initial inspection report from machine entry; latest risk analysis with signature of internal or contracted technical responsible party; stop time validation record after speed change or safety valve actuator replacement; tool list and dies with mass and fixation compatible with interlock; closed maintenance orders citing safety function reactivation after intervention. When an item fails, the finding is not "incomplete paperwork" — it is a documented unsafe condition that can sustain enforcement if repeated after notification.
Large multinational groups sometimes duplicate reports in English for headquarters, but national operations need a Portuguese extract or technical summary referencing the applicable NR-12 annex. Integrators who close SAT without commented PLC and versioned backup shift liability to internal maintenance — and that's where bypass is born.
Typical errors in industrial plants
- Confusing PPE with primary control for mechanical risk when the standard requires fixed guarding or interlock.
- Training operators without revalidating stop time after inverter speed adjustment.
- External maintenance without an order citing lockout and safety function test before returning to production.
- ISO documentation in English in the management system, but machine manual in Spanish in the drawer — inspection demands the language the operator actually reads.
- Ignoring humans in the cell when migrating to a robot vendor promising "package safety" without local layout and circulation assessment.
FAQ
Does Ordinance 344/2024 mandate PLr on every project?
Not in those terms. It amends the glossary; safe control design follows from NR-12 and risk. PLr is an ISO tool to size safety functions when you adopt ISO 13849 as a method.
Can I cite only ISO in legal defense?
Risky. Courts and inspection expect NR compliance. Use ISO as technical support and translation for engineering best practice evidence.
What changed in documentation practice after 344?
Adjust internal glossary and report templates to align terms with NR-1 Annex I and the updated NR-12 Annex IV — avoids debate with auditors on technical standard definition.
What about old machines?
Legacy requires a migration program or documented compensatory controls; "always worked this way" is not a safety policy.
Who is responsible in a turnkey project?
Contract must separate RESPONSIBILITY for safety function validation; integrator and industry share interface when there is modification after SAT.
References
- Brazil. MTE Ordinance No. 344 of March 21, 2024 — amends Annex I (Glossary) of NR-1 and Annex IV (Glossary) of NR-12, among other adjustments per published text. Official publication: Official Gazette of the Union of March 21, 2024; effective on publication date. Consult PDF at: https://www.gov.br/trabalho-e-emprego/ (OHS / Ordinances / 2024) and verification on the National Press Portal — DOU.
- Brazil. Ministry of Labor and Employment. NR-12 — Safety at Work in Machinery and Equipment (consolidated; verify current edition with change history).
- Brazil. NR-1 — General Provisions and Occupational Risk Management (consolidated).
- ABNT NBR ISO 12100 — Safety of machinery — General principles for design — Risk assessment and reduction (ISO family cited in machine engineering).
- ABNT NBR ISO 13849-1 — Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design.
- European Commission / harmonized documentation on Safety of machinery (comparative context for CE markings on imported equipment — does not waive NR-12 in Brazil).
Editorial note: the number and exact content of terms included or excluded from glossaries were described at summary level; to cite them by name in legal opinion, use the full text of the ordinance in the official PDF and the current NR-12 consolidation on gov.br.
