M&E Contractors

In 2017, the team were involved with a project at a local school that required the installation of a new heating system. At a cost of c£1.5million, the job consisted of removing the existing heating system which included all of the existing radiators, pipe work, and boilers as well as part demolition of the existing boiler house tower which housed the header tank and cold water storage tank.

The existing boilers (there were 3) had been in use for just over 40 years and they’d performed well over that time but with one boiler not working, another not working at full capacity and the third performing flat out to make up the shortfalls in the other two, it was time to get the mechanical engineers in to plan a heating system fit for the 21st century.

When we approach a project like this, it’s easy to forget that it’s just a central heating system albeit on a huge scale. Literally, nothing is small when dealing with a system like this; the pipe work, the nuts and bolts, the boilers, everything is on a mammoth scale.

The good news is, that as M&E Contractors we’ve been doing this type of work for years and have the experienced trades people to manage it. Gordon, our site manager is himself a qualified engineer with years of experience and an obvious choice when it came to deciding who was going to head up the project.

Setting aside the task of removing the existing heating system, it was also important that we opened good communication channels with the school and a clear understanding of who we needed to talk to and the different roles each played; after all, we were working in a live school with 1850 children all studying hard for their end of year exams, so a strategy was required to ensure blocks of classrooms could be released with the least amount of disruption to the children and staff.

As classrooms were released, we were able to move in and strip out the existing pipe work in preparation for the M&E Contractors to start installing the new system.

As Mechanical & Electrical Contractors,  it’s important that we stay abreast of the latest methods and innovations; it’s important because it helps us stay ahead of the game and we need to be as fast and efficient as possible to ensure the classrooms were given back to the school ASAP.

Very early on we’d decided we were going to adapt a couple of techniques that would help us expedite the fit out.

• Press fit fittings
• Temporary boiler

 

Compression Fittings

Compression fittings have come on a long way over the last 15 years with new materials and components becoming available. In this particular case we’d decided to use a system by Sanha, the “Sanha Therm series 24000”.

The system consists of tried and trusted SANHA®-Therm press fittings from carbon steel (c-steel) with a black sealing ring from EPDM (ethylene propylene dien rubber monomere) and SANHA®-Therm carbon steel pipes according to EN 10305-3.

The carefully manufactured installation system and its components offer an economically attractive solution for closed heating installations.

 

Fast installation, no risk of fire

The connection with stainless steel pipes by cold pressing enables a fast, time-saving installation and eliminates the risk of fire during the process. NiroSan® installation systems are therefore ideally suited for renovation work and perfect for the school refurbishment we were undertaking.

 

M and E Contractors Utilises Temporary Boiler for Flexibility.

As Mechanical & Electrical Contractors, when we are involved with a project like this we have to give serious consideration to the logistics of the job. Yes, we accept that at the end of the day it’s “just” a central heating system that we are fitting. However, the fact that we are fitting it in an occupied and very active school changes how we do things. We don’t have the luxury normally experienced with a new installation where everything has been planned into the program and more importantly there are no service users to be considered. This is for some a logistical nightmare…but not for us.

As building service engineers we know that one of the key components of installing a new heating system is the transition from old to new. The problem:

• The system being offline = no heating nor hot water
• A build up of debris in the old heating system will likely damage the new boilers if connected.

 

Normally, the removal of the old and installation of the new system takes place on a block by block basis as agreed with the school. It’s impractical to connect the new system to the old boilers due to potential complications that can occur; we want to keep the new system NEW. The solution is to bring in a temporary boiler to run the newly installed systems. Eventually, once all the new installations are in place and tested, the temporary boiler will be running the whole system. At this point it allows us to decommission the old boilers and header tank and install the new ones ready for the new connections.

 

New Boilers

The choice of boiler is critical to how the success of the project will be measured in years to come. On this project, three Hamworthy F250V boilers were used to replace the old boilers.

Hamworthy have been developing boilers for more than 40 years which is reflected in the continual improvement in boiler efficiency and the consequent benefits to users:

• reduced fuel consumption
• lower running costs
• corresponding reduction in carbon emissions

The boilers have many unique features including a cast aluminium alloy sectional heat exchanger, which is rated to 6 bar operating pressure and condensing performance with efficiencies up to 109%.

The large range of outputs enables compact efficient systems to be designed using the optimum number of modules.

• 97% gross seasonal efficiency saves fuel
• Best in class for space saving
• Up to 15:1 turndown
• Close load matching
• Condensing operation saves energy
• Ideal for multiple-boiler applications
• Comprehensive flue options
• Pre-assembled & tested pipe header kits
• Extensive controls capability

Environmental credentials are reinforced by low NOx levels, <40 mg/kWh, achieving European Class 5, and below the threshold for BREEAM specifications.

This is important as Thermal NOx is produced during the combustion process when nitrogen and oxygen are present at elevated temperatures. When nitrogen is released during fuel combustion it combines with oxygen atoms to create nitric oxide (NO). This further combines with oxygen to create nitrogen dioxide (NO2). Nitric oxide is not considered to be hazardous to health at typical ambient concentrations, but nitrogen dioxide can be. Nitrogen dioxide and nitric oxide are referred to together as oxides of nitrogen (NOx).

The pre-mix modulating burner technology is designed for high-efficiency performance and the control system uses the ultra-reliable Siemens platform, which enables a comprehensive range of controls options to be offered. Learn more about our commercial boiler installation here.

Radiators

There are certain things we take for granted; we walk into a room and we expect it to be comfortably warm, it’s expected. But the expertise behind that comfort is rarely considered and that’s how it should be. Radiators and thermostat controls are pretty well invisible to us as end users if all is operating as planned.
When installing radiators in public areas much greater consideration has to be given to the environment or location they will be placed. Hospitals, doctors surgeries, offices, and schools are environments where possibly difficulties could be faced:

• Bacterial infection
• Burns where there is no protective covering to the radiator
• Anti ligature controls to protect vulnerable people
• Anti tamper controls to stop members of the public altering the temperature
• Anti snag surface to stop people from injuring themselves or catching clothing

Stelrad’s range of Low Surface Temperature radiators is the most comprehensive in the UK. They all meet NHS Guidance for ‘safe hot water and surface temperature’ and are finished in antibacterial paint as standard making them the number one choice for safety critical environments.

The radiators are supplied with an attractive, flat panel outer casing, which is totally reversible to allow piping flexibility. Simple and quick to install, the casing is held by security fittings with a unique seam fixing bracket system to prevent unauthorised access to the emitter accommodated inside – and for added protection, the smooth surface is coated in anti-bacterial paint.
The emitter itself provides high outputs through convection for outstanding heating performance. Strictly controlled independent laboratory testing ensures that each emitter is guaranteed to perform to a maximum working pressure of 116 psi (8 bar) and conform to BS EN 442, the European Standard for radiators.

The LST range offers all the specified components required in one robust package and is guaranteed to deliver outstanding performance and dependability.

The LST Standard leaves us as an M and E Contractor free to specify our preferred temperature controls and that’s particularly important in a school where we need to make sure that we have a robust tamper free heating systems with total public safety assured.

The temperature controller we chose was the Herzcules vandal-resistant radiator thermostat that is suitable for installation on Herz valves.

The mounting, dismounting and set-point control is only possible with special tools. It has a locked and concealed set point and features an automatic frost release.

Herzcules serves as both a sensor and control element.

The thermostatic head features components that are visible from the outside:

• Fastening nut – metallic, nickel-plated, with two securing screws (2mm-Allen screws).
• Rib ring – can be rotated around the fastening nut.
• Locking sleeve with indentation.
• Handwheel with set value marks.

The Herzcules thermostat is maintenance free.

Mechanical & Electrical Contractors

Gravitas Build offers a full design package and is able to provide turnkey solutions for your building services needs. As an M and E Contractor we have an engineering team on board whose knowledge adds up to well in excess of 50 years combined experience and we are well placed to deal with your heating installations.

If you would like to find out more about Gravitas Build’s services, have a question or would like us to visit you to discuss your project requirements, please contact us here. We will be pleased to help.

Timelapse Video

What follows is a timelapse video showing the removal of the header tank tower.

If you would like to find out more about Gravitas Build’s services, have a question or would like us to visit you to discuss your project requirements, please contact us here. We will be pleased to help.

Call us on 0121 403 3693 for more information.