IEC 62046 Explained — Placing Protective Equipment: Reach-Over, -Through, -Around and -Under

The familiar distance calculator illustrates arithmetic, not a complete installation approval. ISO 13855:2024 addresses dimensioning and approach geometry as well as distance; IEC 62046 addresses application and commissioning. Use the machine-safety standards index to separate each document’s role and applicable edition before evaluating the layout.

Edition check: IEC’s IEC 62046:2026 catalogue lists Edition 2, published 28 July 2026, replacing Edition 1 of 2018. The revision restructures the document and updates muting, whole-body access, vision/radar information and alignment with ISO 13855. Historical 2018 clause references below must not be treated as verified 2026 numbering. Publication alone also does not establish an EN harmonised reference.

What does IEC 62046 actually cover?

IEC 62046 specifies requirements for the selection, positioning, configuration and commissioning of protective equipment that detects the momentary or continued presence of persons near dangerous machine parts in industrial applications. The devices in scope are the electro-sensitive protective equipment (ESPE) defined in the IEC 61496 series — AOPDs (light curtains), AOPDDRs (laser scanners), and vision-based protective devices — plus pressure-sensitive mats and floors defined in ISO 13856-1. It is written for protecting persons aged 14 and older.

Use the document’s contents to create a project checklist for selection, positioning, stopping performance, restart prevention, muting and device-specific application. The original 2018 discussion referred to Clauses 4–6; because the 2026 revision restructures the standard, check the current text instead of copying the old clause numbers into a compliance file.

How does IEC 62046 relate to ISO 13855 and ISO 13849-1?

Use ISO 13855 positioning guidance for the applicable approach case and current calculation method, then apply IEC 62046 requirements to the actual detection equipment and machine. Evaluate PL or SIL separately for the complete safety function. The old K×T+C shorthand does not capture every 2024 supplement, dynamic approach or reference-plane condition.

One detail from the 2018 edition deserves a flag. It includes a Table 1, “ESPE Types and achievable PL or SIL,” that caps the achievable SIL per IEC 62061 and the achievable PL per ISO 13849-1 by device type. And it states plainly that a SILCL, PL or SIL number on its own is not sufficient to indicate a device's suitability as a safeguard. That sentence should be printed on every purchasing desk. A Type 4 / PL e curtain bolted where a person can reach over it is a high-performance device in an unsafe installation. The rating tells you how reliably it does its job, not whether you gave it the right job.

What are reach-over, reach-through, reach-around and reach-under?

These are the four ways a body gets to the hazard despite the field, and IEC 62046 requires the detection zone — supplemented by mechanical guarding where necessary — to defeat all four. They are simple once you picture them:

• Reach-over — stepping or reaching above a horizontal or angled field. Defeated by the height of the top beam or by an adequate distance for the increased reach.
• Reach-under — crawling or reaching beneath the lowest beam. Defeated by keeping the bottom beam low enough.
• Reach-through — passing a body part through an opening larger than the device's detection capability. This is governed by resolution: a 14 mm finger-detection curtain closes gaps a 40 mm hand-detection one leaves open.
• Reach-around — going past the side of the protected field. Defeated by sizing the field wide enough or by hard guarding the flanks.

Check the detection zone against the actual routes to danger, including platforms, steps, openings, reflection effects and a person remaining inside after crossing. Do not dismiss overreach as outside ISO 13855: positioning and dimensioning are explicitly part of its 2024 scope.

What heights should multiple-beam light barriers use?

The following familiar legacy access-guard layouts are retained to help identify an existing installation. They are not a current-edition design prescription. Before reuse, check beam spacing, reference plane, detection capability, top/bottom limits, reach paths and the selected device manual:

• 2 beams: 400 mm and 900 mm.
• 3 beams: 300, 700 and 1100 mm.
• 4 beams: 300, 600, 900 and 1200 mm.

A low beam and a high beam do not physically prevent crawling or reaching. Suitability depends on detection before hazardous access, the full geometry and any supplementary guards. Horizontal presence fields require their own detection-capability/height analysis; a blanket bottom ≤300 mm and top ≥900 mm rule cannot cover every arrangement.

For a new design, work from ISO 13855:2024 and the applicable IEC 62046 edition. The 2024 revision changes vertical-ESPE limits and approach calculations. Do not infer a universal legal ban on every two-beam device, or approval of every three-beam layout, from the old 400/900 mm example.

What are trip and presence-sensing functions?

A trip function detects entry and initiates the required stop; the machine still takes a finite time to stop. A presence-sensing function detects continued occupation of its covered zone. If a person can pass through and stand outside that zone but inside the hazard area, additional whole-body access and restart-prevention measures are needed.

A DQSA area device or DQC access curtain must be evaluated in its exact installation. Product-family labels do not establish full-floor presence coverage or safe press stopping. Determine whether the field detects entry, continued presence or both, and validate restart prevention for a person left behind it.

How does IEC 62046 govern muting?

Muting temporarily suspends a protective function only while safety is maintained by the applicable alternative conditions. Material transfer is one application; other cases need their own assessment. The 2018 article referred to Clause 5.7 and Annex D; the 2026 edition updates muting requirements, so use its current clauses and the controller manual.

Two crossed sensors or a four-sensor sequence can contribute to material discrimination, but their pattern alone does not prove that a person cannot activate muting. Validate the actual load, gaps, travel direction, speed, timing and foreseeable bypass. Monitor relevant faults and define safe termination; an illustrative geometry does not replace validated safety logic.

Specify the applicable muting indication, fault detection and override behavior from the chosen standard edition and controller manual. Do not treat a lamp, by itself, as proof of a safe muting function. The separate muting versus blanking guide explains why these functions have different coverage implications.

So how do you use IEC 62046 on a real job?

Create a commissioning record covering: document editions; device model and settings; reference planes and every approach path; worst-case stop-time evidence; entry and continued-presence coverage; restart controls; and any muting/override sequence and fault response. Use an approved safe test plan. Reassess after changes to geometry, load, timing or software; a numerical distance and device rating alone do not close the safety case.