INDUSTRY INSIGHT
Detoxifying ethylene glycol
Last month HVR explored the differences between propylene glycol-based heat transfer fluids and its counterpart, detoxified ethylene glycol. So, in the interests of balance, this month we hear the other side of the story. Steve Hickson, managing director at Hydratech dispels the myths behind detoxification and highlights some of the benefits
of detoxified ethylene glycol-based products. Understandably, disruptive technology is often met with uncertainty. For this reason, we continue to invest time and energy in one-on-one due diligence procedures, whether that be for a major dairy chain, government body or micro-brewery. Knowledge is power and without knowing the facts customers won’t have the confidence or incentive to act. So we always encourage potential clients to ask if in doubt. Before delving into the technical detail, these are some pointers often discussed during consultations: • Since 2011 Hydratech has supplied >4.5m litres of DTX to all sectors using RAC, HVAC and renewable energy equipment. • Patent applications and the claims therein must be supported by scientific proof and are subject to rigorous scrutiny to verify efficacy and novelty before the associated patent is granted. • DTX technology has been through that process and a patent granted. • The HSE has reviewed the DTX dossier and confirmed “the results of the studies provide justification that the LD50 of Thermox DTX is outside the range for classification for acute toxicity”. • The Netherlands Food & Consumers Product Safety Authority also performed due diligence on DTX. Its response was “there is no doubt about the classification of the mixture. I have no further questions for you about the Coolflow DTX”. • Since launch, a significant number of blue-chip food and beverage companies have performed independent due diligence into DTX technology and subsequently gone on to convert propylene glycol- based cooling and heating systems to Coolflow DTX, Thermox DTX etc. • Many new-build food and beverage cooling systems are being designed around Coolflow DTX, facilitating a down-sizing of system components, based on improved heat transfer and reduced viscosity. As reported in last month’s article, ethylene glycol
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t’s not often a discovery is made which can make an immediate improvement to safety and energy efficiency, but that’s the case with the DTX range
is toxic to humans and mammals. On initial consumption, there is no immediate reaction in the mouth, throat or esophagus. The problems arise in the stomach and digestive
tract, where specific enzymes are released to break- down the EG. The alcohol dehydrogenese enzyme, ADH for short, gradually converts the EG in to glycoaldehyde. Glycoaldehyde is further metabolised into three highly toxic by-products; glycolic acid, glyoxylic acid and oxalic acid. These three acids cause internal poisoning and
can lead to vomiting, renal failure, blindness and ultimately death. The proactive detoxification of ethylene glycol was
formally investigated in 2001 by two American inventors, Jack Evans and Tom Light of Evans Cooling Systems, Inc. Connecticut, USA. Toxicon, Inc. performed extensive LD50 oral toxicity tests on a range of coolants formulated by Evans and Light, which confirmed the efficacy of the process – to suppress release of the ADH enzyme when EG was ingested. Specifically, through the pre-mixing of specific chemicals in specific proportions with the EG, release of the ADH enzyme was suppressed - hence the EG-component was effectively detoxified. Although the efficacy of the process was quickly accepted by the Patent Office, it took longer for Evans and Light to prove novelty, with the patent being granted on April 30, 2013. Because neat EG is toxic, and must be declared on
any Safety Data Sheet, we painstakingly investigated how SDS for DTX products could accommodate CLP 1272-2008 requirements and still make it clear that the product was non-toxic. Fortunately CLP 1272-2008 includes specific articles (clauses) which can be utilised for such purposes. The following statement is now included within all DTX SDS: In accordance with Article 9 and Article 12 of Regulation (EC) No. 1272-2008 (CLP) Coolflow/Thermox/Solaris DTX has been assessed as a mixture where adequate and reliable scientific information demonstrates the occurance of synergistic and antagonistic effects that renders the
mixture non-toxic, as determined by an EPA-certified laboratory.
Copies of the SDS for DTX were supplied to the HSE along with copies of the patent, Toxicon, Inc. test results, independent coroboration by mediator A/S on behalf of the Danish Environment Agency, plus other relevant documentation. All of these have been collated into the DTX dossier. The final oral toxicity trials performed by Toxicon,
Inc. not only confirmed the animals used for the LD50 tests did not die from ingesting the DTX formula, it documented them actually gaining weight. The written conclusion was that neat DTX formulas had an LD50 rating of >15,000 mg/kg, which is equivalent to propylene glycol. In modern CLP parlance, that equates to ‘no toxic classification’. i.e. DTX has an LD50 of >5,000 mg/kg body weight and therefore is ‘not classified’ within any of the toxicity bands and has no ‘label elements’. With regards to the toxicty or non-toxicity of PG- based products and how they compare with Coolflow DTX, then it is correct to state that neither have been scientifically tested on humans, using the same protocols used in LD50 oral tests on mammals. Previously, under FDA GRAS guidelines small amounts of PG have been used as a humectant in some food stuffs, but that process has now been banned in the EU and is under investigation in the USA. On this subject, the HSE is at pains to point out that no product, not even bottled water, should be labelled as non-toxic, because anything consumed to excess can lead to toxic poisoning. Ultimately, Coolflow DTX and other DTX products
have been proven to be ‘as safe’ as PG, as confirmed on the Safety Data Sheets and vetted by the HSE. So, having verified that DTX formulations pose no
greater risk than PG formulations, the opportunity arises to reduce the cost of process cooling and heating (in systems requiring sub-zero protection) by >10%, as verified by Daiken (DAE), Star Technical Solutions, Siemens, Molson Coors, GE, Johnson Controls, JD Cooling, GEA, Airedale, Aggreko, Swegon, Kensa, Nu-Heat, Ideal and many others.
www.heatingandventilating.net
May 2019
www.heatingandventilating.net
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