EN 1090-2 Execution ClassPro + Studio

FrameAI automatically assigns an execution class (EXC1–EXC4) to every fabrication job using the EN 1090-2:2018 §4.1.2 + Annex B decision matrix. The result appears on the PDF cover sheet, in the Fabrication Requirements tab, and as a SI block in every DSTV NC1 file.

How it works

On every pipeline run FrameAI inspects the computed job data and derives three inputs:

• Consequence Class (CC) — driven by EN 1990 Annex B: structure type, number of occupants, economic consequences. Defaults to CC2 when not specified.
• Service Category (SC) — driven by fatigue and seismic results: SC2 if the fatigue module computed a non-zero Palmgren-Miner damage ratio, or if the seismic module derived a_g·S ≥ 0.10g.
• Production Category (PC) — driven by material grade, welded thickness, and connection complexity: PC2 if any member is above S355, any welded thickness exceeds 30 mm, or any complex (multi-bolt + welded) node is detected.

These three inputs feed into the EN 1090-2:2018 Table B.3 lookup. The result, plus a rationale list referencing specific clauses, is stored as exc_data on the job row.

Entitlement

EXC auto-assignment is included in Pro and Studio. Free-tier users see the EXC value on the demo job only. Upgrade at /pricing.

Decision Matrix — EN 1090-2:2018 Table B.3

CC1 = low consequence (storage, agricultural). CC2 = medium (offices, commercial buildings). CC3 = high (grandstands, public buildings with large crowds). Default is CC2.

Auto-Derivation Rules

Service Category (SC)

• SC2 if the fatigue module ran and computed Palmgren-Miner damage D > 0 on any detail (EN 1993-1-9 §6).
• SC2 if the seismic module ran and computed a_g·S ≥ 0.10g at the site (EN 1998-1 §3.2.1 / EN 1090-2 Annex B §B.2).
• SC1 otherwise.

Production Category (PC)

• PC2 if any member has material grade above S355 (S420, S460, S500, S550, S620, S690…).
• PC2 if any welded thickness exceeds 30 mm (plate thickness in welds_data, or flange/web thickness from extracted_data).
• PC2 if any complex node is detected: a connection with more than two bolt positions AND a weld (multi-bolt + welded combined detail).
• PC1 otherwise.

All derivation decisions are included in the rationale array in the API response, with EN 1090-2 clause references.

NDT Scope — EN 1090-2:2018 Table 24

Tolerance Class

EXC1 + EXC2: Class 1 — essential tolerances only (EN 1090-2 Table D.1.1).

EXC3 + EXC4: Class 2 — functional tolerances including additional requirements on straightness, camber, and end-plate flatness (EN 1090-2 Table D.1.2).

Welder Qualification + WPS/WPQR

• EXC1: EN ISO 9606-1 basic qualification; BPQR sufficient.
• EXC2: EN ISO 9606-1 full qualification; WPQR (EN ISO 15614-1) required for structural welds.
• EXC3: EN ISO 9606-1 strict qualification with periodic renewal; pre-qualified details limited; 3rd-party surveillance.
• EXC4: Highest qualification class with 6-monthly reassessment; all non-standard procedures require separate approval; independent on-site QC inspector.

POST /api/exc/assign

POST/api/exc/assign

Assign EXC class from a job (auto-derives SC/PC) or from explicit inputs. Stores the result in exc_data on the job row.

Request body

{
  "job_id": 42,          // optional — if provided, auto-derives SC/PC
  "cc": "CC2",           // optional override (CC1 / CC2 / CC3)
  "sc": "SC1",           // optional override (SC1 / SC2)
  "pc": "PC1",           // optional override (PC1 / PC2)
  "reason": "Seismic zone upgraded by project engineer",  // optional; logged to job_overrides
  "email": "you@firm.com"  // for entitlement lookup
}

Response

{
  "type": "exc_assignment",
  "job_id": 42,
  "exc": "EXC2",
  "consequence_class": "CC2",
  "service_category": "SC1",
  "production_category": "PC1",
  "rationale": [
    "Consequence Class CC2 per EN 1990 Annex B Table B.1",
    "Service Category SC1 per EN 1090-2:2018 Annex B §B.2",
    "Production Category PC1 per EN 1090-2:2018 Annex B §B.3",
    "EN 1090-2:2018 Table B.3 → EXC2",
    "SC1: no fatigue damage and seismic a_g·S < 0.10g",
    "PC1: all grades ≤ S355, welded thickness ≤ 30mm, no complex nodes"
  ],
  "requirements": {
    "exc": "EXC2",
    "weld_quality_level": "C (EN ISO 5817)",
    "weld_inspection_standard": "EN ISO 17635:2016",
    "ndt": {
      "vt_percent": 100,
      "mt_pt_percent": 10,
      "ut_rt_percent": 0,
      "note": "VT 100%; MT/PT 10% on CJP welds per EN 1090-2:2018 Table 24."
    },
    "tolerance_class": "Class 1 (essential tolerances, EN 1090-2 Table D.1.1)",
    "welder_qualification": "EN ISO 9606-1:2017 (full qualification)",
    "wps_wpqr": "Qualified WPS required; WPQR (EN ISO 15614-1) required for structural welds",
    "fabrication_notes": [...]
  }
}

GET /api/exc/:job_id

GET/api/exc/:job_id

Retrieve stored EXC result for a job. If not yet computed, auto-assigns on the fly. Returns the same structure as the POST endpoint, plus an overrides array listing any engineer manual overrides.

Manual Override

Override the auto-assigned EXC when the engineer has project-specific information (e.g. a regulatory authority requiring a higher class, or a structural certificate confirming lower CC).

curl -X POST https://frameai-structural.polsia.app/api/exc/assign \
  -H "Content-Type: application/json" \
  -d '{
    "job_id": 42,
    "cc": "CC3",
    "sc": "SC2",
    "pc": "PC2",
    "reason": "Regulatory authority requirement — stadium grandstand CC3",
    "email": "you@firm.com"
  }'

Override events are logged to the job_overrides table with user_id, reason, and created_at. They appear in the overrides array on subsequent GET calls.

Sample Rationale Output

A job with S420 members (→ PC2), fatigue D = 0.45 (→ SC2), CC2 environment:

EXC: EXC3

Rationale:
  1. Consequence Class CC2 per EN 1990 Annex B Table B.1
  2. Service Category SC2 per EN 1090-2:2018 Annex B §B.2
  3. Production Category PC2 per EN 1090-2:2018 Annex B §B.3
  4. EN 1090-2:2018 Table B.3 → EXC3
  5. SC2: fatigue module ran with D > 0 (Palmgren-Miner, EN 1993-1-9 §6)
  6. PC2: member C1 grade S420 > S355 (EN 1090-2 Annex B §B.3)

NDT extent (Table 24): VT 100% · MT/PT 20% · UT/RT 20%
Tolerance class: Class 2 (EN 1090-2 Table D.1.2)
Welder qualification: EN ISO 9606-1:2017 (strict, periodic renewal)

References: EN 1090-2:2018 §4.1.2, Annex B (Table B.3); EN ISO 17635:2016; EN ISO 5817:2014; EN ISO 9606-1:2017; EN ISO 15614-1:2017; EN 1993-1-9:2005 §6; EN 1998-1:2004 §3.2.1.