Getting Systems Summer-Ready: Thermal Expansion in High-Temperature Installations
In recent years, the UK and Ireland have experienced a noticeable shift in seasonal temperature patterns. According to the UK Met Office, 2022 was the hottest year on record for the UK, with summer temperatures exceeding 40°C for the first time. Ireland, too, experienced record highs, with Met Éireann reporting its warmest year since records began.
For many industries, these climatic changes may seem like a mere background trend - until system performance and reliability are suddenly compromised. Whether you're working in chemical processing, life sciences, fire protection, or clean water infrastructure, thermal expansion in high-temperature systems is no longer a theoretical concern. It’s a pressing design and maintenance challenge.
🔥 The Thermal Expansion Challenge
Thermal expansion refers to the increase in material dimensions in response to temperature rise. All materials are subject to it, but thermoplastics - such as PP, PVDF, PE, PVC-U, and PVC-C - expand significantly more than metals. This expansion is magnified when both ambient temperature and fluid temperature increase simultaneously, as is increasingly the case during summer months.
For instance, a 10m run of polypropylene (PP) pipe exposed to a 40°C increase in temperature (e.g. 20°C to 60°C) will expand by approximately 6mm. If unaccounted for, this movement can result in:
- Buckling or bowing of the pipeline
- Stress concentration at fixed points
- Leaking joints or ruptured welds
- System downtime and costly repairs
🌤️ Why Summer Heat Changes the Equation
In many external or rooftop installations - common in chemical dosing systems, greywater lines, or fire sprinkler mains - surface pipe temperatures often exceed recorded air temperatures by 10–20°C. These effects are amplified in enclosed plantrooms, service corridors, or areas with radiant heat sources.
Traditional design guidance often assumes conservative ambient baselines. But warmer summers mean those assumptions are no longer valid. For example:
- Roof-mounted dosing lines could exceed 70°C in peak summer sun.
- Black or dark-coloured pipe systems absorb more heat, increasing expansion risk.
- System shutdowns in summer (e.g. for maintenance or cleaning) can create rapid thermal contraction - equally damaging if not managed.
🛠️ Engineering Resilience into Pipe Systems
Modern engineering practices must proactively address these new extremes. At IPS Flow Systems, we advocate a preventative, rather than reactive, approach. Here are the essentials:
1. Know Your Numbers
Use the thermal expansion formula: ΔL = α × L × ΔT
Where:
- ΔL = expansion length
- α = coefficient of linear thermal expansion (material-specific)
- L = length of pipe
- ΔT = temperature change
Materialα (mm/m/°C)Polypropylene (PP)0.15PVDF0.12PVC-C0.08PVC-U0.06Steel~0.012
Even small ΔT values can add up over long pipe runs.
2. Incorporate Expansion Loops or Offsets
Expansion must be given space to occur. Use:
- Offset legs designed to absorb movement
- Loop configurations in long straight runs
- Flexible couplings and expansion joints where movement cannot be redirected
We recommend installing at calculated intervals - and IPS can support you with the required spacing charts and layout drawings.
3. Anchor and Guide Points Correctly
- Anchors: Fix the pipe at designated locations to prevent uncontrolled movement
- Guides: Allow directional movement while limiting lateral displacement
This helps the system absorb force predictably, without compromising joints.
4. Reassess Fixings and Support Spacing
- Increase support frequency for higher temperatures
- Use sliding supports, roller hangers, or low-friction clamps
- Avoid rigid metal clips that can create pressure points
This is particularly important in systems using larger-diameter or wall-thinner pipes.
5. Choose the Right Jointing Method
High temperatures can degrade certain joint types faster. We recommend:
- Socket fusion or electrofusion for PE and PP
- Butt fusion for industrial applications
- Mechanical couplings or flanged joints for easy disassembly
- Where solvent cement is used (e.g. in PVC-C), choose high-temp certified versions and follow precise curing protocols
6. Don’t Overlook Insulation
Thermal insulation is not just for cold climates. In hot environments, it:
- Reduces surface heating from solar radiation
- Minimises ΔT fluctuation
- Prolongs pipe life and improves expansion predictability
🧭 What the Standards Say
The importance of accounting for thermal expansion is well-documented across multiple standards:
- BS EN ISO 15494 – Industrial thermoplastic piping design
- WRc Guidelines – Performance of water and chemical piping systems
- LPCB and FM Global standards – Fire protection compliance
- ISO 14692 – Guidelines for thermoplastic pipework in process industries
Designing for thermal expansion isn’t a luxury - it’s part of code compliance and good engineering.
🧩 How IPS Flow Systems Supports You
With decades of experience supporting high-temperature plastic piping systems, IPS Flow Systems is uniquely positioned to help your team design with confidence. Our services include:
✅ Material data and design charts
✅ Pipework layout reviews for expansion loops and offsets
✅ Jointing guidance and compatibility checks
✅ Training and site support for installers
✅ Specialist product ranges including expansion bellows, flexible couplings, and thermal insulation materials
✅ Stock availability with next-day delivery throughout the UK and Ireland
We are more than a supplier - we’re your engineering partner.
🌍 Building Resilience in a Warming World
As climate models from UKCP (UK Climate Projections) predict longer and more intense heatwaves by mid-century, the systems we build today must be ready for the conditions of tomorrow.
Thermal expansion will remain one of the most frequently overlooked causes of system failure - unless it becomes an everyday design mindset. At IPS, we’re here to help make that transition easy.
📞 Ready to Talk?
Let’s make your systems summer-ready.
UK: 0191 521 3111 Ireland: +353 1 2573741 Email: sales@ipsflowsystems.com Web: www.ipsflowsystems.com
📚 References:
- UK Met Office: https://www.metoffice.gov.uk
- Met Éireann 2022 Annual Climate Statement: https://www.met.ie
- BS EN ISO 15494: Plastics Piping Systems
- WRc Standards: https://www.wrcplc.co.uk
- UK Climate Change Risk Assessment 2022 – HM Government