The route to successful commissioning
Problem-free commissioning — Steve Hills.
The latest Building Regulations emphasise the importance of commissioning in creating a heating system that is compliant with the regulations, energy efficient and cost effective. STEVE HILLS says that unless commissioning is completed correctly, the chances are the system will not be performing to its design specification.Commissioning boiler plant correctly gives a system that does what it is designed to do. The market is continually moving to more sophisticated products, and it is important to be familiar with, and trained in, getting the most out of the equipment being installed. Plan
A key element of successful commissioning is the preparation of a commissioning plan. A good place to start is the CIBSE Commissioning Code M, which provides an overview of the management arrangements required to ensure that building-services systems are commissioned to meet the objectives of Part L of the latest Building Regulations. More specific for boilers is the CIBSE Commissioning Code B, which presents current standards for good commissioning practice, in the form of recommendations and guidance, dealing with the work stages required to commission boilers If you are investing in high efficiency and condensing boilers, you want them to perform to their design specification. It is also vitally important that ancillary items of equipment are correctly installed and integrated with the boilers — such as the controls, pumps, pressurisation set and flue system. Inexperience with the products can mean delays in commissioning while engineers familiarise themselves, often involving dialogue and telephone calls with the manufacturer, particularly when things are not going well, and sometimes in desperation searching for the O&M manuals that are despatched with every product. Hamworthy has a 2-pronged approach to support commissioning of its products. It is in our best interests to ensure products are set up right first time and given the best possible start to a long and reliable life. We recognise that there are many experienced contractors who undertake commissioning themselves. We provide them with product training and support, either in our training centres or on site, giving them the benefits of our experience to work with our products quickly and effectively. This training can cover commissioning, servicing and general fault finding, and familiarisation with new products as they are introduced. Alternatively, we can commission the boilers on behalf of the contractor, using our experience directly to ensure the plant will perform to design expectations. There are great benefits to be gained by using the original-equipment manufacturer (OEM) to commission a heating system. OEMs are familiar with their product and know how it should be commissioned to gain optimum performance, not withstanding the ability to provide good service strategy for the building operator and applying an extended warranty if undertaking commissioning on behalf of the contractor. As an additional benefit, when we commission a system, our standard 2-year parts warranty is extended to cover labour, and extended warranties up to five years are also offered. Boilers are individually fired and tested in the factory prior to delivery, ensuring that the design combustion settings are correct and controls are working properly and that the boiler will perform to specification when subsequently installed and commissioned correctly. Service engineers are fully trained, equipped and competent to work on our products and undertake all of the necessary pre-commissioning checks. The commissioning service includes pre-commissioning checks for the service systems and covers fuel supply, water, flue, electrics and controls. Boiler system checks include all connections, interlocks and safety features. A potential problem identified at commissioning stage could avoid significant compared with being undetected until other symptoms emerge. Preparation
Prior to commissioning, several important steps need to be completed. The system should be filled and vented, with the necessary circulating pumps running prior to commencing boiler commissioning. A gas-tightness and purge certificate is required before commissioning can begin. Safety systems need to be fitted and fully operational, including safety valves, fuel shut-off devices, fanned flue and/or pressurisation-unit interlocks. The controls, once connected, should be operable and calling for heat. Where not fully in operation, it should be possible to run the plant in manual mode without affecting any safety interlock. Plant-room ventilation should have been completed and adequate for the system. One of the most important requirements of successful commissioning is to ensure that the combustion parameters are within acceptable limits. Any deviation could result in poor combustion performance with higher emissions of carbon dioxide, lower efficiency and lower output. Additionally, incorrect placement of sensors can lead to short-cycling, increasing wear and tear on the boiler and may ultimately lead to premature boiler failure. This is something an experienced service engineer can observe and draw to the attention of the commissioning management. Log books
Boiler Log Books are another useful commissioning benefit. Hamworthy was instrumental in the introduction of boiler logbooks as part of a BCEMA initiative back in 2000. Now, the logbook supports the Building Log Book as required in Part L. The boiler logbook records commissioning data and can build up a service history, which can be exceedingly valuable to visiting engineers who can see what the original settings were and what has been done to the plant subsequently, thereby making diagnostics much simpler in future. With good planning and using experienced engineers, commissioning can be a problem-free procedure if done correctly from start to finish. Savings can be made, and the project can be completed on time. The system will perform to design specifications and have a longer, trouble-free life. Steve Hills is commercial director with Hamworthy Heating Ltd, Fleets Corner, Poole, Dorset BH17 0HH.