DELUGE PROTECTION SPECIFICATION DTS 01:91
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Electrical equipment on offshore installations may be located in areas which are equipped with the emergency deluge facilities. Exposure of such equipment must not lead to water ingress in quantities which could cause the equipment to become a potential source of ignition when exposed to a flammable atmosphere.
The introduction of DTS 01 created a standard method of tests to be carried out on electrical equipment, components, devices and motors to simulate their exposure to realistic water deluge conditions and establish their potential hazard. This was considered to far outreach any of the Ingress Protection tests that were already performed under the IEC 60529 standard, as longer term exposure to the typical marine and offshore environment often brought with it more onerous conditions than those anticipated by IEC 60529.
The Deluge Test utilises a salt water solution controlled at predetermined temperatures and this is applied using medium velocity nozzles at a pressure in the range of 3.5 to 4.5 bar. To make the test most realistic an additional pre-conditioning is applied to the samples to be tested. This pre-conditioning (section 4.2) can optionally consist of either exposure to vibration or thermal ageing depending upon the nature of the equipment under test. The purpose of this pre-conditioning is to simulate accelerated ageing of the seals used in the equipment prior to the tests being conducted, which is considered to be equivalent to 20 years of service at normal operating temperatures.
With cable glands it is more logical to have their sealing rings subjected to the rapid thermal ageing rather than vibration exposure tests. The cable glands and sealing rings are conditioned in a humidity chamber for 14 days, at 95ºC and a relative humidity of 90%.They are then further subject to a temperature of 100ºC for 14 days, prior to the deluge test commencing. Then they are installed into equipment which is heated to simulate its operating temperature at a typical ambient, and are subjected to a cold water deluge spray, creating an internal vacuum, which would draw water through the cable glands into the equipment if the deluge seal did not perform.
At CMP, the ageing of cable gland seals, taking into account such things as the heat cycling effects of electrical apparatus, is seen as having a major bearing on proving true long term protection against deluge conditions. Significantly, CMP has had the confidence in having a number of its innovative Cable Glands, including the T3CDS range tested to this onerous requirement. Under the close third party scrutiny, and the rapid ageing specification described above, CMP has been able to demonstrate the durability of its products in these conditions, whereas not all cable gland manufacturers have been able to meet the exacting demands of this criterion.
One of the features of a true deluge proof cable gland for armoured, or braided, cables which makes it stands out above other standard cable glands is the inclusion of a deluge seal. This deluge seal is applied in the joint where the cable gland body terminates the cable braid armour and it is included for protection against a specific and costly problem that has been experienced in offshore environments around the world. Prior to the introduction of high powered emergency deluge systems the problem that was experienced in the most hostile offshore situations was frequent yet often premature cable braid armour corrosion. This corrosion was occurring due to the ingress of water through the armour termination compartment of the cable gland, even when a cable gland had passed an Ingress Protection test of IP66 or higher. Following investigation, the evidence pointed to the fact that during energising and de-energising of the electrical equipment the heat cycling effects were causing positive and negative changes in the internal pressure of the equipment. This change in pressure was in turn causing water to work its way around the threaded joints in the cable gland via a capillary action that meant the cable braid would in time be contaminated by salt water. This often led to rapid deterioration and even corrosive breakdown of the cable braid that was commonly made of Galvanised Steel Wire. In the experience of major oil and gas operating companies, this known problem was first discovered as a serious problem when earth continuity checks highlighted the fact that there was no continuity through the cable at all.
Tackling this serious problem and also going one step further in addressing the requirements of the Deluge Test at the same time, when potentially more frequent exposure to salt water conditions would result, CMP Products was the first manufacturer to introduce a Deluge Proof cable gland design. This design of course featured a positive sealing function between the cable gland components that make up the armour termination joint, like the example shown below. It should be recognised that whilst it may be possible to obtain an IP67 or IP68 rating with a cable gland that does not include a deluge seal feature, it is highly unlikely that such a product would pass the conditions of the DTS 01 : 91 Deluge Test and realistically ensure long term cable armour preservation in offshore or marine installations.
The results of the tests that CMP has had carried out confirm that its range of Deluge Protected Cable Glands can be safely specified for use in deluge conditions, in the sure knowledge that their long term performance will maintain protection against the ingress of water.
This has been a major factor in the decision making process of a number of major Clients on key projects in both the offshore and marine industry as well as other exposed onshore facilities. Cable Gland products that feature a deluge seal are not only intended for the offshore oil and gas industry, but are also equally suitable for use in the Water Treatment industry, or anywhere where the process equipment may be subject to occasional submersion or flooding.The specific range of CMP Cable Glands which fully comply with the Deluge Test specification DTS01 includes, but is not limited to :-
- Triton CDS (T3CDS & T3CDSPB family) Armoured Cable Gland
- E1* Series Deluge Option (e.g. E1UD, E1FUD family) Armoured Cable Gland
- Protex 2000 (PX2K family) Armoured Compound Barrier Cable Gland.
- Sureseal 2000 (SS2K) Double Seal Unarmoured Cable Gland.
- Protex Sureseal 2000 (PXSS2K) Unarmoured Compound Barrier Cable Gland.
- A2F Unarmoured Cable Gland
- C2K Armoured Cable Gland
- Marine Cable Glands for Wet Locations
Please refer to specific product information for product compliance