Contaminated Water Diving Updated 2/18/08

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                                                     Diving in contaminated water with the DESCO Air Hat                                              Hunter Pro-HRM Drysuit Information 

WARNING:

Diving in contaminated water is very hazardous. It should not be attempted without through training and proper equipment.

DESCO recommends using a free flow style diving helmet with a double exhaust valve, mated to an appropriate drysuit, for contaminated water diving operations.

Demand vs. free flow.

Our intent is to point out the clear advantage our helmet has in performing in the worst chemical, biological, and nuclear contamination environments. When mated to the Hunter Pro-HRM drysuit the DESCO Air Hat provides the best available protection to the diver.

In contaminated diving situations doing away with the demand feature and going "free flow" is the logical and safest course. The DESCO Air Hat is the preferred helmet for contaminated water diving. The “free flow” through the helmet assures constant overpressure is maintained. Having air constantly passing out of the exhaust valve greatly reduces the potential for contaminates to leak back into the helmet. This feature is especially desirable when diving in highly caustic or dangerous environments such as fuel tanks, acid storage tanks, or nuclear fuel transfer pools.

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Increasingly, divers are asked to work in contaminated environments. Harbors, urban rivers, sewage treatment plants, and nuclear power stations are just a few places a diver may find a jobsite. A demand helmet suffers from a susceptibility to a basic law of physics. Operation of the demand valve will cause fluctuation in the pressure differential and potentially permit leak back of contaminated water through the exhaust valve. Double exhausts reduce the chances of contaminated water leaking back into the helmet. Stacking additional exhaust valves will further reduce the likelihood of leak back but this adds more working parts to the helmet. This does not change the fact that constant outflow is the best way mitigate leak back.

Another consideration is if leak back occurs on a free flow helmet the leaked water will normally collect in the bib, neck dam, or body of the dry suit.  On a demand helmet the water will be leaked back into the oral/nasal where the diver can ingest it through inhalation or swallowing.

The advantage the DESCO Air Hat has over a demand helmet is the free flow design maintains a constant overpressure and minimizes the potential for leak back.  It is the standard helmet for use in inland contaminated diving.

In the lower part of this page is the test data for Hunter rubber drysuits.

The U.S. Navy has issued a revised U.S. Navy Contaminated Water Diving Guidelines

as of January 15, 2008.

Click here for a full PDF of the current

U.S. Navy Contaminated Water Diving Guidelines on the Supervisor of Salvage website.

You will need Adobe Reader to access file.

Additional websites with information pages on contaminated water diving:

NOAA Diving Program: Contaminated Water Diving Reports

OSHA: Hazardous waste operations and emergency response. - 1910.120

The Dry Suit:

Hunter Pro-HRM Drysuit

HUNTER POLLUTED WATER DIVING TESTS

CHEMICAL PERMEATION AND BIOLOGICAL PENETRATION TESTS FOR HUNTER PRO-AM 1050, PRO-HD 1500 AND PRO HRM 1200 VULCANISED RUBBER MATERIALS AND SEAMS

It is widely acknowledged that in order to dive safely you need to know the level of protection given by your equipment. Especially as chemical and biological contaminants in water are a fact of life, and it is not always possible to know at any given time what contaminates are present.

In order to provide this guide to the performance of our dive suits we contracted the Texas Research Institute (TRI) to test our rubber suit materials and seams against a battery of chemicals and oils.
The Chemical Testing was performed as follows:

• Tests were performed to two method standards: ASTM F739-96 which are particularly applicable to American and Canadian markets, and EN369 which is particularly applicable to European markets.

• Tests were carried out across the material with a seam, on Pro-AM and Pro-HD materials against 21 chemicals and oils.
Further tests were then carried out on Pro-AM, Pro-HD and Pro-HRM materials only without a seam, and against a battery of 8 of the most aggressive chemicals and oils.

The results are an average of three cells.
Tests were carried out ACROSS THE SEAM as it has been the experience of the TRI that seams in all types of material (not just dive suits) often exhibit flaws during chemical permeation testing.

The Bacterlophage Test was carried out as follows:
• Tests were performed to ASTM F1671 standards.
• Tests were carried out at 2 pressure settings and 3 different exposure levels.
• Tests were carried out on NEW MATERIAL ACROSS THE SEAM.

The results are intended as a guide, and are to be used as such to determine the suitability of the suit for each anticipated exposure.
 

The suit should be used in conjunction with a suitable glove and ring system to protect the hands, and also a helmet yoke and helmet system to protect the head.

Decontamination of the whole system should be commenced as soon as the diver exits the water, and the suit and attachments e.g. seals, should be regularly inspected to determine whether the suit should be used again or disposed of.

CHEMICAL PERMEATION TEST RESULTS
[MATERIAL SEAMS]
 

This data was derived from testing in accordance with ASTM Standard F739-96 and EN369. These tests were performed under laboratory conditions. Hunter neither warranties nor guarantee protection provided by the use of this material against the tested chemical.

The user should determine the applicability of test conditions when assessing the suitability of material for actual anticipated exposure.

CHEMICAL PERMEATION TEST RESULTS

[MATERIAL]

CHEMICAL PERMEATION TEST RESULTS

[MATERIAL]

This data was derived from testing in accordance with ASTM Standard F739-96 and EN369. These tests were performed under laboratory conditions.

Hunter neither warranties nor guarantee protection provided by the use of this material against the tested chemical.
 

The user should determine the applicability of test conditions when assessing the suitability of material for actual anticipated exposure.

BACTERIOPHAGE TEST ASTM F1671 [MATERIAL SEAMS]

The viral penetration test method ASTM 1671 is used to assess the effectiveness of materials used in protective clothing for protecting the wearer against contact with blood-borne pathogens using a surrogate microbe suspended in a body fluid stimulant under conditions of continuous liquid contact.

Protective clothing material pass/fail determinations are based upon the detection of viral penetration.
 

Exposure to biological fluids containing viruses which cause HEPATITIS B (HBV), HEPATITIS C (NBC), and ACQUIRED IMMUNE DEFICIENCY SYNDROME (HIV) can pose significant risks to health and life. This test method has been specifically defined for modelling viral penetration by these three viruses transmitted in blood and other potentially infectious body fluids.

The material is challenged for a specified time and pressure sequence with a nutrient broth containing Phi-X174 bacteriophage which is not pathogenic to humans, but which does infect bacteria.

After the challenge time is complete the inside surface of the material is washed with sterile nutrient broth to collect any bacteriophage which may have penetrated the material barrier.

The solution is then assayed using E.coli C bacteria in agar media to determine the presence of bacteriophage.

This is indicated by the formation of plaques (measured in plaque forming units (PFUs)) in the bacterial lawn of the agar media.
 

Plaques are the visible clear areas in the E.coli C bacterial lawn where the bacteria have been destroyed by bacteriophage infection and cell break-up.

ANY EVIDENCE OF VIRAL PENETRATION FOR A TEST SPECIMEN CONSTITUTES FAILURE.
 

BIOLOGICAL PENETRATION TEST RESULTS

These tests were performed under laboratory conditions.
 

Hunter neither warranties nor guarantee protection provided by the use of this material against the tested chemical.
 

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