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Home / Case studies / District heating / No.02 — Palencia DH · Buried network stress
Case study · No.02 · District heating · Buried pipe stress
Phase I — Extension 1 · EN 13941 Class C

A network only delivers when it moves with the street.

A buried, pre-insulated district heating network through the urban core of Palencia, Spain.

Sector
District heating
Location
Palencia · Spain
Engagement
Flexibility & pipe stress
Year
2022
28,0 MW centralised generation
6.400 dwelling-equivalents served
96% CO₂eq cut vs. baseline
C EN 13941 class · full procedure
Editorial schematic · DH-022-01 · not to scale Phase I — Extension 1 · 4 service-line categories on a single trunk
DH-01 28,0 MW CENTRAL · BIOMASS + SOLAR + GN DN 250 · 95 / 65 °C PRIMARY TRUNK · SUPPLY / RETURN NEW BUILDING SCHOOL RESIDENTIAL EN 13941 · CLASS C FULL PROCEDURE · NO SIMPLIFIED METHOD CAESAR II · EN 13941 §6 / §7 · VERIFIED AGAINST EN 13480-3
Zone under analysis · primary trunk
Modified service connection
Relocated service connection
New service connection
The brief

A focused review against code.

A focused review against code.

Out of scope

What we deliberately did not do.

What we deliberately did not do.

  • Process suitability of the lines
  • Material specification
  • Hydraulic design
  • Primary & secondary support structural design
  • Equipment nozzle qualification
  • Erection & assembly
  • Commissioning
What we found

Nine green sheets and one revealing failure.

Nine of the ten systems came back inside admissibles in every case.

The three welds passed. The system did not.

The finding

Passing in the welds we reviewed doesn't mean passing as a system.

A weld can sit well below admissible stress while the line it belongs to is over admissible at the global level.

The DN100 line was the only one of the ten where this gap mattered.

Line
Service water · DN100
Welds reviewed
3
all within EN 13480 admissibles
System result
Over admissible
Action
Reported to client

The frame the report was signed against.

A stress report is only as authoritative as the frame it cites.

Design code

EN 13480

European code for industrial metallic piping.

Industrial · process piping
Equivalent code

ASME B31.3

The American process-piping equivalent.

Process piping · USA & international
Software

CAESAR II

Industry standard for pipe stress and flexibility analysis.

Hexagon · v10
Load cases

W · P · T · Combinations

Self weight, pressure, thermal gradient, combinations.

Sustained · operating · occasional
Methodology

From a folder of as-builts to a signed report.

01

Reading the as-built

Isometrics, piping spec, 3D model, site photographs.

02

CAESAR II modelling

Geometry, supports, equipment connections, boundary conditions, fluid.

03

Conservative hypotheses

Where information about a line's continuation is missing, the line is closed at that node as a fixed point.

04

Traceable delivery

Main report and one annex per line. Every number traces back to a node.

Got a stress review that needs a second pair of eyes?

We work in CAESAR II against EN 13480 and ASME B31.3.

Sector
Pulp & paperProcess plant · northern Spain
Discipline
Pipe stress & flexibilityAs-built design review
Software
CAESAR IIHexagon · v10
Code
EN 13480Equiv. ASME B31.3
Year
2022Q1