LEAK DETECTION
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Mitigating costs
Tom Burniston of Bacharach looks at the importance of leak detection as a managing factor of F-Gas impacts.
U 10
nder the F-Gas regulations, January 2018 sees the start of a sharp phase-down in the amount of HFC refrigerant that will be available to the EU market, with a reduction to 63% of the 2015 baseline figure. This is a steep reduction from the 93% availability in 2017 and the refrigeration industry is feeling the effects.
The latter half of 2017 saw, for example, the price of R404A increase by 700%. R404A, with a Global Warming Potential (GWP) of 3,922, is not alone in seeing these exceptional price increases. It is one of a group of gases with a GWP >2,500 that will be banned from use in stationary refrigeration equipment from 2020 (excepting equipment designed to cool below -50°C). This list includes R507, R422A, R422D, R434A and R428A.
The rising prices are not, however, restricted to these gases. R134a, with a GWP of 1,430, has also seen increases in the region of 400%, with a similar situation for many other commonly used refrigerants, including R407C and R410A. 2018’s reduction in HFC
availability is expected to see prices continuing to increase. Whilst some commentators have been vocal in their criticism that industry has not sufficiently prepared for the changes driven by F-Gas, the lower GWP refrigerants that can be used as replacements, including HFOs and HFO/HFC blends, do not carry the same comparatively low price- tag that the industry was used to
previously. Higher refrigerant prices are expected to become a global phenomenon as producers struggle to meet end-user requirements whilst staying within their production quota.
Standards for refrigerant leaks Leaking refrigerant becomes ever more expensive. It has been estimated that in many cases the cost of refrigerant loss is now higher than the cost of a technician’s time to repair a leak.
F-Gas does mandate that
permanent leak detection systems be installed on large systems containing a refrigerant charge greater than 500 tonnes CO2
equivalent. There
are also reductions in the frequency of leak checking requirements if permanent leak detection is installed for refrigeration systems containing
greater than five tonnes CO2 equivalent. The regulations do not, however, provide any guidance as to the type of leak detection systems that can be used, nor their respective capabilities.
Historically, much of the installed base of leak detection equipment has been targeted at meeting code requirements from refrigeration safety standards such as EN 378:2016, which in its requirements for refrigerant leak detection is broadly similar to other internationally used refrigeration standards, including ASHRAE 15. The goal of these standards is clear: ensuring the safe use of refrigerants, and the safety of
personnel working with and around refrigeration systems. The ensuing requirements of EN 378:2016 are that the concentration at which a leak must be detected is relatively high for refrigerants of A1 safety classification, running upwards of 15,000 parts per million (ppm) in many cases. By contrast, ASHRAE 15 determines a detection level of 1,000 ppm for many of these A1 refrigerants. Either way, in most refrigerated spaces and machinery rooms, reaching these levels would require a catastrophic leak of a large volume of refrigerant.
Monitoring refrigerant leakage at levels of 1,000 ppm (or higher) can therefore be viewed as an effective way to enhance the safe use of refrigerants. It does not provide a method for catching smaller refrigerant leaks, which can nevertheless result in a significant and increasingly expensive loss of refrigerant.
Reducing refrigerant leak rates Given the growing cost of replacing and topping-up refrigerant, implementing a strategy to reduce refrigerant leak rates is coming more sharply into focus. This cannot be achieved by using detection systems looking for leaks in the region of 1,000 ppm, as often in place for refrigeration safety.
Low-level leak detection is available and field proven, with a number of manufacturers offering detection systems with a minimum detectable level in
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