Lifecycle Stage 02
Standards Selection
Standards Selection Decision Tree
flowchart TD
A[Concept brief] --> B{Market?}
B -->|US| C[NEC · NFPA 79 · UL 508A]
B -->|International| D[IEC 60204-1 · ISO 12100]
B -->|Both| E[Dual compliance set]
A --> F{Safety functions?}
F -->|Machine| G[ISO 13849-1 or IEC 62061]
F -->|Process SIS| H[IEC 61511]
A --> I{Networked / remote?}
I -->|Yes| J[IEC 62443]
A --> K{Hazardous area?}
K -->|Yes| L[IEC 60079 or NEC Art. 500/505]
C --> M[Register + type A/B/C hierarchy]
D --> M
E --> M
G --> M
H --> M
J --> M
L --> M
1. Purpose of This Stage
This stage translates the concept-stage outputs — system description, boundary definition, market identification, and machine type — into a definitive, project-specific register of applicable standards that will govern all subsequent design, build, verification, and documentation activities.
Standards selection is not administrative. It is an engineering decision with direct consequences:
- Selecting the wrong standards means designing to requirements that do not satisfy the applicable regulatory framework — resulting in non-compliance discovered at commissioning, shipment, or audit
- Missing a type-C standard means designing to generic type-B requirements when more specific (and often more stringent or more permissive) requirements exist for that machine type
- Failing to identify conflicts between standards (e.g., NFPA 79 vs IEC 60204-1 wire color conventions) means discovering them during detailed design when changes are expensive
- Not deciding the PL vs SIL pathway at this stage means the risk assessment in Stage 3 cannot assign targets using the correct methodology
This stage answers: What rules are we designing to, and where those rules conflict, which takes precedence?
2. Entry Criteria
This stage begins when Stage 1 (Concept) exit criteria are met.
Required Inputs
| Input | Source (Stage) | Why It Matters |
|---|---|---|
| System description | Stage 1 | Determines which type-C standards apply based on machine function |
| Machine / system boundary definition | Stage 1 | Determines what is inside the scope of standards compliance |
| Market and regulatory identification | Stage 1 | Determines which national/regional codes and directives apply |
| Operating mode definitions | Stage 1 | Some standards have specific requirements per operating mode (e.g., ISO 10218 for collaborative robot modes) |
| Type-C standard preliminary identification | Stage 1 | Starting point — to be confirmed and expanded here |
| Customer specification / contract | Sales / customer | May mandate specific standards, editions, or certifications |
| Assumptions register | Stage 1 | Any unresolved assumptions that affect standards applicability |
If market identification is not confirmed from Stage 1, this stage cannot produce a reliable standards register. Resolve before proceeding.
3. Standards Influence
| Standard | Role at This Stage |
|---|---|
| ISO 12100:2010 | Defines the type-A / type-B / type-C hierarchy that governs how standards interact and which takes precedence |
_standards_map.md |
Internal routing document — primary tool for mapping project characteristics to applicable standards |
| Decision workflow crosswalk | Internal tool for resolving PL vs SIL pathway selection |
| EU Machinery Directive 2006/42/EC / Machinery Regulation (EU) 2023/1230 | If CE marking is required, the list of harmonized standards determines which standards provide presumption of conformity |
| EU Official Journal (OJ) | Current list of harmonized standards under the Machinery Directive — must verify that the edition you are using is the one currently listed |
| OSHA standards (29 CFR 1910) | If US market, OSHA references specific consensus standards — these are not optional if cited in the contract or if OSHA jurisdiction applies |
| Customer specification | May mandate specific standards, editions, or deviations — these override default routing in some cases |
4. Standards Hierarchy — How Standards Interact
Before selecting standards, understand how they relate to each other:
┌─────────────────────────────────────────────────────────────┐
│ TYPE-A: Basic safety standards (fundamental concepts) │
│ ISO 12100 │
│ Applies to ALL machinery │
└──────────────────────────┬──────────────────────────────────┘
│
┌──────────────────────────▼──────────────────────────────────┐
│ TYPE-B: Generic safety standards │
│ │
│ B1 — Safety aspects: B2 — Safeguarding devices: │
│ • ISO 13849-1 (PL) • ISO 13850 (e-stop) │
│ • IEC 62061 (SIL) • ISO 14119 (interlocking) │
│ • IEC 60204-1 (electrical) • ISO 13855 (safety distance)│
│ • ISO 13857 (reach distances)• IEC 61496 (light curtains) │
│ • IEC 61508 (functional • ISO 14120 (guards) │
│ safety umbrella) │
│ Applies to wide range of machinery │
└──────────────────────────┬──────────────────────────────────┘
│
┌──────────────────────────▼──────────────────────────────────┐
│ TYPE-C: Machine-specific safety standards │
│ │
│ • ISO 10218-1/2 (robots) │
│ • ISO/TS 15066 (collaborative robots) │
│ • ISO 16092 (presses) │
│ • ISO 11161 (integrated manufacturing systems) │
│ • ISO 11553 (laser processing machines) │
│ • ISO 13732 (packaging machinery) │
│ • EN 415 (packaging machinery) │
│ • EN 619 (conveyors) │
│ Applies to specific machine type │
│ │
│ ★ TYPE-C OVERRIDES TYPE-B where they conflict ★ │
└─────────────────────────────────────────────────────────────┘
The Override Rule
Per ISO 12100 Introduction:
When a type-C standard deviates from one or more provisions dealt with by a type-A or type-B standard, the type-C standard takes precedence.
This means: If ISO 10218-2 specifies a particular safety distance calculation method for robotic cells, that method takes precedence over the generic ISO 13855 method — even if ISO 13855 would give a different result. You must identify type-C applicability before finalizing your type-B standards selections.
5. Engineering Activities
5.1 Confirm Market and Regulatory Requirements
Validate and expand the market identification from Stage 1:
| Question | Answer Needed | Impact |
|---|---|---|
| Is CE marking required? | Yes / No | If yes: Machinery Directive/Regulation applies, harmonized standards provide presumption of conformity |
| Is NRTL listing required (UL, CSA)? | Yes / No / Specific NRTL | If yes: UL 508A (panels), UL 61010 (test equipment), etc. |
| Is the machine installed in the US? | Yes / No | If yes: NEC (NFPA 70) governs field wiring, NFPA 79 governs machine electrical |
| Is the machine installed in Canada? | Yes / No | If yes: CEC (CSA C22.1), CSA standards may apply |
| Does the customer specification mandate specific standards? | List them | Customer mandates may add to or override default selections |
| Are there site-specific requirements? | List them | Some facilities (pharmaceutical, automotive, semiconductor) have internal standards that exceed published standards |
| Is the machine subject to process safety regulation? | Yes / No | If yes: IEC 61511 / IEC 61508 pathway, potentially OSHA PSM (29 CFR 1910.119) |
5.2 Identify All Applicable Type-C Standards
This is the most commonly missed activity at this stage. Use the machine type identified in Stage 1 to search for applicable type-C standards:
| Machine Type | Potentially Applicable Type-C Standards |
|---|---|
| Robotic system / robotic cell | ISO 10218-1, ISO 10218-2, ISO/TS 15066, ANSI/RIA 15.06 |
| Press / stamping system | ISO 16092 series, ANSI B11.1 through B11.19 |
| Integrated manufacturing system | ISO 11161 |
| Packaging machinery | EN 415 series |
| Conveyor system | EN 619, ANSI/ASME B20.1 |
| Laser processing machine | ISO 11553, IEC 60825-1 |
| Woodworking machinery | EN 691 (general), machine-specific EN standards |
| Printing machinery | EN 1010 series |
| Machine tools | ISO 16090 series |
| Food processing machinery | EN 1672-2 |
| Rubber and plastics machinery | EN 289, EN 201 (injection molding) |
| Lifting equipment / cranes | EN 13001, EN 15011 |
If no type-C standard exists for your machine type, document that determination explicitly. The project will then rely entirely on type-A and type-B standards.
If the machine is a combination of types (e.g., a robotic press tending cell), identify all applicable type-C standards and note where they overlap or conflict.
5.3 Apply the Routing Logic
The _standards_map.md routing document provides the primary decision logic. The expanded routing is:
START
│
├─► Is the machine / system for the US market?
│ │
│ ├─ YES ──► NEC (NFPA 70) — field installation
│ │ NFPA 79 — machine electrical safety
│ │ UL 508A — if control panel NRTL listing required
│ │ ANSI B11 series — if applicable machine type
│ │ ANSI/RIA 15.06 — if robotic system (US version of ISO 10218)
│ │ OSHA 29 CFR 1910 Subpart O — general machine guarding
│ │ OSHA 29 CFR 1910.147 — lockout/tagout (LOTO)
│ │
│ └─ NO ───► Skip US-specific codes
│
├─► Is the machine / system for the EU market (CE marking)?
│ │
│ ├─ YES ──► ISO 12100 — risk assessment (type-A)
│ │ IEC 60204-1 — electrical safety of machinery
│ │ ISO 13849-1 OR IEC 62061 — functional safety (see 5.4)
│ │ ISO 13857 — safety distances (reach over, through, around)
│ │ ISO 13855 — safety device positioning (approach speed)
│ │ ISO 13850 — emergency stop design
│ │ ISO 14119 — interlocking devices (if guards with interlocks)
│ │ ISO 14120 — guards (fixed, movable)
│ │ IEC 61496 — light curtains (if used)
│ │ Applicable type-C standard(s) from 5.2
│ │
│ └─ NO ───► Skip EU harmonized standards (unless customer requires)
│
├─► Is the machine for BOTH US and EU (global)?
│ │
│ └─ YES ──► Apply BOTH sets above
│ Identify conflicts (see 5.5)
│ Default to MOST RESTRICTIVE requirement from each
│ Document conflict resolution in standards register
│
├─► Are safety functions present or anticipated?
│ │
│ ├─ YES ──► Select PL or SIL pathway (see 5.4)
│ │ ISO 13849-1 → Performance Level (PL a through e)
│ │ IEC 62061 → Safety Integrity Level (SIL 1 through 3)
│ │ IEC 61508 → if umbrella / complex / novel system
│ │
│ └─ NO ───► Document why no safety functions exist
│ (rare — most machines have at least e-stop)
│
└─► Is this a process safety application (SIS/SIF)?
│
├─ YES ──► IEC 61511-1/2/3 — process sector functional safety
│ IEC 61508 — foundation standard
│ ISA 84.00.01 — US adoption of IEC 61511
│ OSHA PSM 29 CFR 1910.119 — if applicable process
│
└─ NO ───► Skip process safety standards
5.4 PL vs SIL Pathway Selection
This is a preliminary decision made here and confirmed at Stage 3 after risk assessment. The decision determines which methodology is used to assign safety integrity targets.
| Factor | Favors ISO 13849-1 (PL) | Favors IEC 62061 (SIL) |
|---|---|---|
| Machine type | Standard machinery, discrete manufacturing | Complex machinery with extensive safety PLC logic |
| Customer requirement | Customer specifies PL | Customer specifies SIL |
| Industry norm | Most machinery OEMs in EU use PL | Process industry, some automotive OEMs prefer SIL |
| Subsystem complexity | Simple to moderate (relay-based, hardwired, small safety PLC programs) | Complex (multiple safety PLCs, networked safety, extensive diagnostics) |
| Existing company practice | Team is experienced with SISTEMA and PL calculations | Team is experienced with SIL calculations and IEC 62061 methodology |
| Type-C standard requirement | Type-C standard references ISO 13849-1 | Type-C standard references IEC 62061 |
| Regulatory context | CE marking, Machinery Directive | Process safety, IEC 61511 (always SIL) |
Important notes:
- ISO 13849-1:2023 and IEC 62061:2021 have been significantly harmonized — either can be used for machinery applications
- You cannot mix PL and SIL within a single safety function — one function, one methodology
- You can use different methodologies for different safety functions on the same machine (though this adds complexity and is generally discouraged)
- For process safety (SIS/SIF), the pathway is always SIL via IEC 61511 — there is no PL option
- Document the rationale for the pathway selection — auditors will ask why
5.5 Identify and Resolve Standards Conflicts
For global projects (US + EU, or multi-market), conflicts will exist. Identify them now, not during detailed design.
| Topic | NFPA 79 (US) | IEC 60204-1 (EU) | Resolution Approach |
|---|---|---|---|
| Wire color — protective earth | Green or green/yellow | Green/yellow only | Use green/yellow (satisfies both) |
| Wire color — neutral | White or gray | Light blue | Must decide per market OR use dual-labeled |
| Wire color — ungrounded conductors | Any color except green, white, gray | Any color except green/yellow, light blue | Use black (satisfies both) |
| Control circuit voltage | 120V common | 24VDC or 230V common | Specify per project — document basis |
| Overcurrent protection | Per NEC Article 430 | Per IEC 60204-1 §7 | Apply most restrictive |
| Disconnect requirements | NFPA 79 §5.3 | IEC 60204-1 §5.3 | Generally aligned — verify specific requirements |
| Grounding / earthing | NEC Article 250 | IEC 60204-1 §8 | Apply both — document compliance to each |
| Panel enclosure rating | NEMA types | IP ratings per IEC 60529 | Provide NEMA-to-IP cross-reference, design to most restrictive |
| Emergency stop color | Red on yellow background | Red on yellow background | Aligned (ISO 13850 governs both) |
Document every conflict resolution decision in the standards register with rationale.
5.6 Identify Applicable Type-B2 Standards (Safeguarding Device Standards)
Based on the preliminary hazard scan from Stage 1 and the anticipated safeguarding approach, identify which device-specific standards will apply:
| If You Anticipate Using… | Applicable Standard |
|---|---|
| Emergency stop devices | ISO 13850 |
| Guard interlocking devices | ISO 14119 |
| Fixed and movable guards | ISO 14120 |
| Light curtains / AOPDs | IEC 61496-1 and applicable part (e.g., -2 for type 4) |
| Two-hand control devices | ISO 13851 |
| Pressure-sensitive mats / edges | ISO 13856-1, -2, -3 |
| Enabling devices (hold-to-run) | ISO 11161 Annex A, IEC 60204-1 §9.2.6 |
| Safety distances (reaching over/through/around) | ISO 13857 |
| Safety device positioning (approach speed) | ISO 13855 |
| Trapped key interlocks | ISO 14119 |
5.7 Verify Standard Editions
Standards are revised. Using an outdated edition can mean non-compliance:
| Check | Action |
|---|---|
| Is the edition you are referencing the current published edition? | Verify against ISO, IEC, ANSI, or NFPA catalog |
| If CE marking: is the edition listed in the EU Official Journal as a harmonized standard? | Verify against the current OJ listing — a standard can be current but not yet harmonized, or harmonized but withdrawn |
| Does the customer specification require a specific edition? | If yes, use that edition (even if not the latest) and document |
| Has a new edition been published since project start that changes requirements? | If yes, assess impact and decide whether to adopt — document decision |
| What is the transition period (if a new edition was recently published)? | Some standards have a transition date after which the old edition is withdrawn |
6. Key Deliverables
| # | Deliverable | Description |
|---|---|---|
| 1 | Standards register | Formal list of all applicable standards with applicability basis, scope, edition, and conflict resolution notes (see expanded template below) |
| 2 | PL vs SIL pathway selection record | Documented decision with rationale for which functional safety methodology will be used, per safety function or for the project as a whole |
| 3 | Type-C standard applicability determination | Documented search and conclusion — either the applicable type-C standard(s) or a statement that none applies, with basis |
| 4 | Standards conflict resolution log | For multi-market projects: list of identified conflicts between standards with resolution and rationale for each |
| 5 | Updated assumptions register | Any new assumptions identified during standards selection, added to the register from Stage 1 |
Expanded Standards Register Template
| # | Standard | Edition | Applicable? | Basis for Applicability | Scope / Applicable Sections | Harmonized (EU OJ)? | Conflict Notes | Verified By | Date |
|---|---|---|---|---|---|---|---|---|---|
| 1 | NEC (NFPA 70) | 2023 | Yes | US installation, per contract | Articles 409, 430, 670 | N/A (US code) | — | [Name] | [Date] |
| 2 | NFPA 79 | 2024 | Yes | US machinery electrical, per contract | All chapters | N/A (US standard) | Wire color conflicts with IEC 60204-1 — see conflict log | [Name] | [Date] |
| 3 | UL 508A | 4th Ed. | Yes | NRTL listing required per customer | All sections | N/A (US listing) | — | [Name] | [Date] |
| 4 | ISO 12100 | 2010 | Yes | CE marking, type-A | Full standard | Yes | — | [Name] | [Date] |
| 5 | ISO 13849-1 | 2023 | Yes | CE marking, PL pathway selected | All clauses | Verify OJ listing for 2023 edition | — | [Name] | [Date] |
| 6 | IEC 60204-1 | 2016 | Yes | CE marking, EU electrical | All clauses | Yes | Wire color conflicts with NFPA 79 — see conflict log | [Name] | [Date] |
| 7 | ISO 10218-2 | 2011 | Yes | Robotic cell — type-C applies | All clauses | Yes | Overrides ISO 13855 safety distance calculation per type-C precedence | [Name] | [Date] |
| 8 | ISO 13857 | 2019 | Yes | Safety distances for guards | Tables 1–4 | Yes | ISO 10218-2 may override for robot-specific scenarios | [Name] | [Date] |
| 9 | ISO 14119 | 2013 | Yes | Interlocked guards present | All clauses | Yes | — | [Name] | [Date] |
| 10 | ISO 13850 | 2015 | Yes | E-stop devices present | All clauses | Yes | — | [Name] | [Date] |
| 11 | IEC 62061 | 2021 | No | PL pathway selected instead | — | — | Retained as reference for subsystem SIL data if needed | [Name] | [Date] |
| 12 | IEC 61511 | 2016+A1 | No | Not a process safety application | — | — | — | [Name] | [Date] |
Every “No” entry must have a documented basis for exclusion, not just a blank.
7. Exit Criteria — Gate Review
This stage is complete when all of the following are true:
| # | Criterion | Evidence |
|---|---|---|
| 1 | Standards register is complete with all applicable type-A, type-B, type-B2, and type-C standards identified | Completed register with all columns filled |
| 2 | Every standard in the register has a confirmed edition and applicability basis | Edition column and basis column complete for all entries |
| 3 | Type-C standard applicability is confirmed or explicitly ruled out with documented rationale | Type-C determination record |
| 4 | PL vs SIL pathway is selected with documented rationale | Pathway selection record |
| 5 | For multi-market projects: all known conflicts between standards are identified and resolution is documented | Conflict resolution log |
| 6 | Harmonized standard status is verified against current EU OJ listing (if CE marking applies) | OJ verification date recorded |
| 7 | Customer-mandated standards are included and any deviations from default routing are documented | Customer requirements cross-referenced in register |
| 8 | Standards register is reviewed by at least one person other than the author | Review signature, date, comments resolved |
| 9 | Stage 1 assumptions affecting standards selection are resolved or explicitly carried forward | Updated assumptions register |
If the PL vs SIL pathway is not decided, Stage 3 cannot proceed — the risk assessment methodology depends on this decision.
8. Roles and Responsibilities
| Role | Responsibility |
|---|---|
| Safety / Controls Engineer | Owns this stage — authors the standards register, performs the routing logic, selects PL vs SIL pathway, identifies type-C standards, identifies conflicts |
| Project Manager | Ensures this stage is completed before detailed engineering begins; confirms market and contract requirements are communicated to the safety engineer |
| Mechanical / Process Engineer | Confirms machine type classification for type-C standard identification; identifies any process-specific standards (e.g., food safety, pharmaceutical GMP) |
| Sales / Application Engineer | Confirms customer-mandated standards, certifications, and market destinations; resolves ambiguities in customer specification |
| Quality / Compliance | Verifies harmonized standard status against EU OJ (if CE marking); confirms NRTL listing requirements (if US market) |
9. Common Mistakes
| Mistake | Consequence | How to Avoid |
|---|---|---|
| Type-C standard is not identified | Design proceeds under generic type-B requirements; late discovery causes rework or non-compliance | Systematically search for type-C standards by machine type — use the table in 5.2 as a starting checklist |
| Using an outdated edition of a standard | Design may comply with withdrawn requirements but not current ones; CE presumption of conformity may not apply | Verify editions against current catalogs and EU OJ at the start of the project |
| PL vs SIL pathway not decided | Risk assessment in Stage 3 cannot assign targets; engineers use ad hoc methods; calculations are inconsistent | Make the decision here, document rationale, confirm at Stage 3 |
| Standards conflicts not identified for global projects | Discovered during detailed design or build — causes wire re-pulling, label changes, panel rework | Run the conflict check in 5.5 for every multi-market project |
| “We always use these standards” without project-specific verification | Prior project may have been a different machine type, different market, or different customer — standards applicability is project-specific | Start from the routing logic every time, even if the result is the same |
| Customer specification references standards without edition | Ambiguous — which edition did they mean? | Clarify with customer in writing before finalizing register |
| Standards register is created but never updated | New standards or editions published during a long project; scope changes add new machine types | Assign an owner and a review trigger (scope change, phase gate, or quarterly for long projects) |
| Non-applicable standards are simply left blank instead of explicitly excluded | Auditors cannot tell whether the standard was considered and excluded or simply overlooked | Every standard considered must have a “Yes” or “No” with a documented basis |
10. Relationship to Adjacent Stages
┌──────────────────────────────┐
│ STAGE 1: CONCEPT │
│ │
│ Provides: │
│ • System description │
│ • Machine type │
│ • Market identification │
│ • Type-C preliminary ID │
│ • Operating modes │
└──────────────┬───────────────┘
│
▼
┌──────────────────────────────┐
│ STAGE 2: STANDARDS │ ◄── You are here
│ SELECTION │
│ │
│ Produces: │
│ • Standards register │
│ • PL vs SIL pathway │
│ • Type-C confirmation │
│ • Conflict resolution log │
└──────────────┬───────────────┘
│
│ All outputs feed directly into
▼
┌──────────────────────────────┐
│ STAGE 3: RISK ASSESSMENT │
│ │
│ Uses: │
│ • Standards register to │
│ determine which risk │
│ assessment methodology │
│ applies │
│ • PL vs SIL pathway to │
│ determine how targets │
│ are assigned │
│ • Type-C standards for │
│ machine-specific hazard │
│ requirements and pre- │
│ defined safety measures │
└──────────────┬───────────────┘
│
▼
┌──────────────────────────────┐
│ STAGE 4: SAFETY ARCHITECTURE │
│ │
│ Uses: │
│ • Standards register to │
│ determine architecture │
│ requirements (categories │
│ per ISO 13849-1 or HFT │
│ per IEC 62061) │
│ │
│ STAGE 5: DETAILED DESIGN │
│ │
│ Uses: │
│ • NFPA 79 / IEC 60204-1 │
│ for electrical design │
│ • UL 508A for panel design │
│ • Conflict resolution log │
│ for multi-market wiring │
│ decisions │
└──────────────────────────────┘
11. Reference: PL ↔ SIL Approximate Equivalence
For reference only — these are approximate equivalences, not exact conversions:
| Performance Level (ISO 13849-1) | SIL (IEC 62061) | PFH range |
|---|---|---|
| PL a | — | ≥ 10⁻⁵ to < 10⁻⁴ |
| PL b | SIL 1 | ≥ 3 × 10⁻⁶ to < 10⁻⁵ |
| PL c | SIL 1 | ≥ 10⁻⁶ to < 3 × 10⁻⁶ |
| PL d | SIL 2 | ≥ 10⁻⁷ to < 10⁻⁶ |
| PL e | SIL 3 | ≥ 10⁻⁸ to < 10⁻⁷ |
Do not use this table to convert between PL and SIL after the fact. Choose one methodology and apply it consistently.
12. Templates and Tools
| Resource | Purpose |
|---|---|
_standards_map.md |
Primary routing logic document |
| Decision workflow crosswalk | PL vs SIL pathway selection tool |
| Standards register template | Spreadsheet with all columns per Section 6 |
| Type-C standards lookup table | Reference list of machine types and corresponding type-C standards |
| Conflict resolution log template | Table for documenting multi-market standards conflicts and resolutions |
| EU Official Journal harmonized standards list | External reference — verify at EU harmonized standards database |
Trust Boundary — Engineering Judgment Required
This site is an independent educational reference for industrial automation standards. It paraphrases and organizes guidance in original language; it is not a substitute for the official published standards, professional engineering judgment, or legal review, and content has not been independently verified against current published editions.
Items marked Review pending await technical review against the identified edition. Items marked Planned have no reviewed source material behind them. Do not rely on this site for compliance determinations, safety-critical design decisions, or legal interpretation.