In breve
UNI EN 17975:2025 is the first European standard that harmonizes the management of risks from energies and fluids during maintenance. It has been in force in Italy since 24 July 2025 and defines four isolation processes (reinforced, standard, neutralization, specific provisions), introduces the Try-Out phase and requires traceability and formalized roles for every LOTO operation.
Why UNI EN 17975:2025 exists
A significant share of serious industrial accidents happens during maintenance,
due to the accidental reactivation of energies or fluids. Until now, in Europe,
each company managed its Lockout/Tagout procedure according to internal
practices, often inspired by the American standard OSHA 29 CFR 1910.147. The
new UNI EN 17975:2025 fills that gap: it is the first harmonized European
reference defining a common vocabulary, roles, processes and quality criteria
for safe isolation.
The standard is not a law with direct sanctions. It is, however, the state of
the art to which any employer will have to refer in order to demonstrate the
adoption of good practices consistent with Italian Legislative Decree
D.Lgs. 81/08. In other words: in the event of an accident, failure to apply it
can reveal organizational shortcomings.
What "LOTO" means and how the 17975 fits in
Lockout/Tagout is the procedure by which the energy sources of a machine or plant are physically isolated before a maintenance operation, locking devices (lockout) and warning tags (tagout) are applied, and accidental reactivation is prevented.
The 17975 introduces a third step in the cycle: the Try-Out, that is, the actual verification that isolation has occurred before starting work. Hence the term LOTOTO (Lock Out, Tag Out, Try Out) that the standard codifies as the standard sequence.
The four isolation processes
The most operational novelty of the 17975 is the formalization of four levels of
isolation, to be chosen on the basis of the risk assessment (based on
UNI EN ISO 12100). The default choice is the most restrictive one.
Reinforced isolation (RI)
The standard level required by the standard. In addition to locking the energy isolation device, an additional physical separation is introduced: removing a section of piping, inserting a blind flange, mechanical disconnection. It guarantees the highest level of safety and is the default choice unless there are documented technical or operational obstacles.
Standard isolation (SI)
Classic LOTO: a padlock is applied to the energy isolation device and a tag is attached. Traceable, but it does not offer the additional physical separation of RI. When SI is adopted instead of RI, the standard requires documented compensatory measures.
Neutralization through control systems (N)
Isolation is achieved through the machine's functional safety (e.g. safety doors, disconnection logic managed by the safety PLC). Possible only if the control system is safety-rated and the risk assessment allows it.
Specific provisions (SP)
Dedicated procedures for particular activities (e.g. operations on plants that cannot be stopped). Always subject to a specific risk assessment.
What changes compared with previous practice
For Italian companies that already applied LOTO procedures according to OSHA best practices, the 17975 does not overturn the "how it is done", but it tightens the "how it is documented" and the "who is responsible". Three practical changes:
The choice of isolation level must be justified. It is no longer enough to apply a padlock to a valve: if you do not reach RI you must explain why and what compensatory measures you adopt.
The "gray areas" must be defined. The standard recognizes that many recurring maintenance activities are carried out by line operators rather than specialized maintenance staff. For these areas — operations that are not "true" maintenance but not ordinary production either — roles, responsibilities and procedures must be clarified.
Training is no longer informal. Field experience alone is not enough: structured, recorded, periodically verified training is needed. The safety officer (RSPP), maintenance staff, supervisors, operators and designers have distinct responsibilities that the standard lists explicitly.
Parent/child lockout: managing complex plants
On a real plant, isolating a single energy source is often not enough. An operation on a packaging line, for example, may require the simultaneous isolation of electrical supplies, compressed air, steam and product flows. When these isolations are interdependent — one "parent" controls several "children" — the 17975 requires the hierarchy to be managed formally, with sequential release rules and traceability of who unlocks what and when.
Historically this is managed with LOTO cabinets and paper registers. On plants with dozens of isolation points, practice shows its limits: sequence errors, lost tags, registers filled in afterwards. The standard does not impose a digital solution, but it makes the audit trail a substantial requirement.
How to comply: an operational checklist
A pragmatic path to align with the 17975 in an existing production site:
- Mapping. Survey all machines and plants, identify every energy source (electrical, mechanical, pneumatic, hydraulic, thermal, chemical) and every isolation point.
- Risk assessment by activity. For each typical maintenance operation, define which isolation process to apply (RI by default, otherwise justify).
- Procedures and devices. Write the isolation procedures point by point, equip yourself with the devices (padlocks, tags, blind flanges) and the management cabinets.
- Roles and responsibilities. Formalize who authorizes, who applies, who verifies (Try-Out), who removes. Have the procedures signed.
- Structured training. Distinct programs for the safety officer, maintenance staff, supervisors, operators. Recording and frequency.
- Traceability. Adopt a tool that records every application and removal of a lockout, ideally digital for managing the parent/child relationships and the audit trail.
- Periodic audit. Annual verification of the effectiveness of the procedures, with simulations and a review of real cases.
The Eurosystem experience
Eurosystem has operated since 1990 in regulated pharmaceutical sites, where LOTO management is a daily matter and the GMP audit does not forgive misalignments between procedure and practice. From this experience came SmartLOTO, the patented intelligent LOTO cabinet system with selective padlock release and a digital audit trail, designed expressly around the requirements of the 17975: native management of parent/child relationships, automatic recording of operations, and a procedural constraint on the Try-Out phase. It is not the only way to comply, but it is the way we translated the standard into hardware and software for the sites where we operate.
Related regulatory references
D.Lgs. 81/2008— Italian Consolidated Workplace Safety Act (legal framework)UNI EN ISO 12100:2010— Safety of machinery, general principles for design and risk assessmentUNI EN ISO 14118:2018— Prevention of unexpected start-upOSHA 29 CFR 1910.147(US) — historical reference for LOTOANSI/ASSP Z244.1-2016(US) — Control of Hazardous Energy
Domande frequenti
Is UNI EN 17975:2025 mandatory?
It is not a law with direct sanctions: it is a voluntary technical standard. In practice, however, it is the state of the art that can be invoked to demonstrate compliance with the Italian D.Lgs. 81/08. In the event of an accident, not having applied it may amount to organizational shortcomings.
Since when has it been in force in Italy?
It was adopted by UNI and entered into force on 24 July 2025.
What is the difference between reinforced (RI) and standard (SI) isolation?
Reinforced isolation adds a physical separation beyond the padlock (blind flange, removal of a section of piping, mechanical disconnection). Standard isolation stops at locking the energy isolation device. The standard indicates RI as the default, with SI allowed only with documented compensatory measures.
What does Try-Out mean and why is it important?
It is the actual verification that isolation has occurred before starting the operation (e.g. attempting to start the machine with the safety devices in place to confirm that it does not start). The 17975 formalizes it as a mandatory step of the cycle, hence the term LOTOTO.
Can LOTO still be managed with paper registers?
The standard does not impose digital solutions, but it requires substantial traceability and the management of hierarchical isolations (parent/child). On complex plants, paper quickly shows its limits; practice suggests adopting tools that automatically record operations and constrain the procedural sequence.
Which company figures must be involved?
The employer, the safety officer (RSPP), supervisors, maintenance staff, line operators and designers. The standard clarifies the responsibilities of each and requires structured, recorded training, no longer entrusted to field experience alone.