09 February 2023
The Institute of Refrigeration (IOR) Technical Committee has been discussing the key elements required to ensure effective handover of plant to the client, in line with standards and codes of practice to ensure best and safe system operation. This article reflects the IOR Guidance contained in its Safety Codes of Practice for various refrigerants.
When a refrigeration system is reaching the end of the installation process and the client is about to assume responsibility for it for the rest of its working life there are a few key steps that should not be missed, but this is often a frantic time with urgent deadlines to be met and sometimes it is tempting to skimp on these things in order to deliver on time.
A key part of this final stage is the commissioning process. Often this is confined to a simple exercise of setting the system to work and demonstrating that the room, cabinets or process have reached the desired temperature. There is so much more to good commissioning and it is the opportunity to deliver benefit both for the installation contractor and for their client.
Commissioning ought to be a three-step process with three key subject areas. The three steps are setting the system to work, fine-tuning its performance and feeding back operating data to the system designer for them to confirm that it is performing in line with their expectations. The three subject areas are reliability, safety and efficiency. Clearly it is not nearly enough to prove that temperature has been reached. The commissioning process should give confidence that temperature will be maintained without interruption, that it will be done without risk to people or property and that it does not use too much electricity to achieve the result.
If the installation programme has been delayed then the start of commissioning may be late, but the end date usually doesn’t move – indeed often it cannot move because the store opening date is fixed, or contracts for chilling or freezing need to be fulfilled. This is the point at which the commissioning team may find that their life becomes impossible. It’s a classic rock vs hard place situation.
There are several steps that a wise client can take to make sure that they get their facility on time and in the best possible condition to ensure long term satisfaction. Early communication with the contractor is essential, recognising the pressures that they are under to complete the programme on time, and affording them as much flexibility as possible while retaining a clear statement of all the objectives that need to be met before the project can be considered to be complete. In this regard it is helpful to consider the whole project to be an ongoing process, not a one-off event. It is like bringing a plane in to land: the pilot doesn’t fly to a point 5,000 feet above the airfield and just stop flying. Instead he starts lining up with the runway several miles away and gradually descends, making small adjustments along the way until the wheels finally connect with the tarmac, hopefully in a smooth, bump-free glide.
Photograph: Star Refrigeration
The contractor has to give the client honest progress appraisals all through the project and be prepared to be flexible in order to meet key dates along the way. This requires a high degree of trust on both sides and that’s not something that can be created in an instant; nor should it ever be assumed or taken for granted. The set-up of the contract between the parties plays an important part in this because both sides need to demonstrate a commitment to looking out for the best interest of the other party. A heavy-handed contract with heavy indemnity and liability clauses or unreasonable payment terms can be extremely counter-productive in this regard, whereas the right contract can help to build trust.
This is not the same as no contract at all: what is required is fairness and clarity of purpose. It should go without saying that the contract should be written in understandable plain English and should be discussed by both sides to ensure there are no misunderstandings. If this is done then the risk of the commissioning start date being delayed are reduced but it may still happen that external circumstances cause a delay. In this case early discussion of the situation is invaluable.
If the start of commissioning has to be delayed then nothing from the commissioning process should be sacrificed but it might be necessary to switch around the sequence of events to suit operational needs. This is where the concept of “beneficial use” is valuable. In a perfect world the installing contractor would complete all of their safety checks, then they would performance test the system and produce detailed performance reports to confirm with the designer that everything is as intended before leaving the performance benchmark with the client for future reference.
If commissioning is squeezed for time then it may be possible to satisfy a short term process demand before the final fine-tuning, performance recording and feedback has been completed. It is even possible that this is a better way to proceed because it allows the client to gain real experience of operating the plant before the final commissioning is finished and builds an early picture of what good performance looks like. The sooner a benchmarking exercise is started the better – it is crazy to wait for a year or two and then decide that some form of energy, reliability or safety tracking would be a good idea.
Modern monitoring software provides the opportunity to do this benchmarking in much more detail than has previously been possible. Ideally this should start at the beginning of the commissioning period and should log all of the performance parameters through that time although it must be recognised that the initial efficiency may seem poor because the system may still be “running in”, or pulling down in temperature, which can take several weeks on a large installation. If a “digital twin” of the plant can be created before the commissioning period starts it will provide additional reassurance that everything is in good order by the time the handover date arrives. It can also help to validate system performance for the design ambient and full load conditions even though the weather is cold or the load is light during the commissioning.
Clients should be looking for a set of operating logs including records of maintenance interventions (changing filters, checking lubricant, drive alignments) as well as key temperature and pressure parameters around the system. Details of typical good practice in commissioning are given in the Institute of Refrigeration Safety Codes of Practice, particularly in Section 6, Section 8 and Appendix F. Before the plant is handed over to the client it is being operated by the installation contractor, who is therefore responsible for having a written scheme of examination for the plant under the Pressure System Safety Regulations (SI 128/2000). The plant should be inspected in accordance with the written scheme before it is put into operation. Of course, the client does not have to adopt the written scheme prepared by the installation contractor if they prefer to have a common format across all their sites, but it can be helpful to ensure commonality of the written schemes used before and after handover.
- IOR Refrigerant Safety Codes of Practice are available for all key refrigerant types including carbon dioxide, ammonia, flammables (including A3 and A2L HFOs) and non-flammable/lower toxicity (including HFCs).