IDWe Pipe Freezers delivered a live pipe isolation service for The Portland Hospital in Central London. The job required the replacement of two six inch gate valves on cold water storage tanks – without draining down the system. Using liquid nitrogen pipe freezing, our Pipe Freezing Services team isolated sections of six inch copper mains safely and quickly. We enabled for valve replacements to be carried out by others without affecting hospital operations, water supply, or patient care.
Live Valve Replacement in London Using Liquid Nitrogen Pipe Freezing Services
Location: The Portland Hospital, Great Portland Street, London W1W
Sector: Healthcare / Private Hospital
Client: 4i Water Services Ltd
Service Provided By: IDWe Pipe Freezing
The Challenge
The Portland Hospital is a busy, private healthcare facility with critical systems running 24/7. Shutdowns or drain-downs would risk major disruption to services and patient areas. The valves feeding cold water storage tanks had to be replaced. However, the building required the system to stay live, with zero interruption. We needed a precise solution to isolate the pipework without draining water or shutting off supply.
Our Solution: Pipe Freezing Services in a Live System
Our team carried out the works during two carefully planned out-of-hours visits. We used liquid nitrogen freezing to form temporary ice plugs inside the pipe. These plugs allowed the client to isolate the affected sections and replace the gate valves safely. We reinstated pipework insulation and cleared the area after each visit.
Visit 1: First Valve Isolation and Replacement
- Engineers arrived with equipment and full PPE
- Removed insulation from around the six inch copper mains
- Installed pipe jackets to prepare for controlled freezing
- Applied two six inch nitrogen freezes – one on each side of the first valve
- Waited until the ice plugs had fully formed
- 4i Water Services replaced the first gate valve
- We released the freezes and checked the joints for leaks
- Reinsulated the pipe and cleared all work materials
Visit 2: Second Valve Replacement
- Repeated the full process for the second gate valve
- Formed ice plugs using pipe freezing services on either side of the second valve
- Allowed for 4i Water Services valve replacement to proceed safely
- Released the freezes, leak-checked, and reinstated the insulation
- Cleared all leftover materials and waste from site
The Pipe Freeze Outcome
- Two large six inch gate valves replaced without draining the system
- Full water supply remained live throughout the hospital
- Zero disruption to patients, services, or staff
- Work completed safely and efficiently during low-activity hours
- The site was left clean, tidy, and fully operational
Why Pipe Freezing Was the Right Solution
Pipe freezing offers fast, targeted isolation for valve replacements and pipe modifications. It prevents system downtime and removes the need for draining thousands of litres of water. Our method forms solid ice plugs that temporarily block water flow. The process is safe for high-pressure systems and widely used in healthcare and commercial sites. Unlike mechanical alternatives, pipe freezing services use no extra fittings or long drain times. It’s ideal for urgent works, planned maintenance, and sensitive locations.
What is Pipe Freezing?
Pipe freezing creates an internal ice plug using ultra-cold temperatures. At IDWe Ltd, we use liquid nitrogen to freeze the pipe’s contents inside pipe jackets.
This ice plug isolates the section safely and can withstand normal operating pressure. It allows engineers to work on live systems – without shutdowns, drain-downs, or contamination risk.
Our freeze seals are effective on copper, steel, plastic, and mixed-material systems. We freeze pipe diameters from 8mm up to over 12 inches across multiple industries.
>> To learn more, please read our full guide
Need Pipe Isolation Without Shutdown?
IDWe Pipe Freezers work across London, helping engineers isolate live pipework. We support M&E contractors, facility managers, and building maintenance teams with precision freezing services. Our service is fast, clean, and ideal for hospitals, labs, hotels, schools, and commercial buildings. Let us help you avoid unnecessary shutdowns or delays.
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Can we help you with your next project? Get in touch today for a quote or expert advice, please call 020 8302 7644 or email info@idwe.co.uk
We can adapt our services to suit your industrial and commercial needs, learn more about our pipe freezing services.
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