A study to test the benefits and drawbacks of using a dive mask in helicopter underwater escape – the first study of its kind – was completed in late May in St. John’s, Newfoundland and Labrador. The Marine Institute’s Offshore Safety and Survival Centre (OSSC) undertook the 18-month project with funding support from Petroleum Research Newfoundland and Labrador (PRNL), which funds and facilitates collaborative research and development on behalf of the province’s offshore oil and gas industry. The study fits with PRNL’s strategic focus for HSE, which is to develop technologies to reduce risks for operation in arctic and harsh environments.

The Canadian Association of Petroleum Producers endorsed the study through its Atlantic Canada Safety Committee.

Atlantic Canada is believed to be the only jurisdiction in the world where dive masks are carried on helicopters used to transport personnel to and from offshore installations which, in Newfoundland and Labrador, are located more than 300 km (180 miles) from the primary shore base. Elsewhere, nose clips are typically provided as an option on suits. Since there are no regulations mandating that dive masks be used in helicopter underwater escape training or in practice, their use in Atlantic Canada is optional.

The use of dive masks in connection with helicopter underwater escape traces its origins to a 1989 study on the performance of masks in a helicopter underwater escape trainer (HUET) egress. “The study conducted by Chris Brooks confirmed that the dive mask increases the wearer’s ability to see ambient illumination under water at certain distances,” said Kerri-Ann Evely, marine safety researcher at OSSC. The offshore helicopter transport providers in Newfoundland and Labrador subsequently began including the masks among the equipment provided onboard, and OSSC began incorporating the masks into its training.

Currently, Cougar Helicopters carries them on board the Sikorsky S-92s that provide this service for Hibernia Management Development Corp., Suncor, Husky Energy, and Encana. “Some instructors believe that students wearing dive masks have more confidence and less anxiety when putting their face in the water,” said Evely. In addition, the mask provides nose occlusion and would protect the eyes from any fuel that might be present in the water following a ditching incident. These considerations, along with a lack of regulatory guidance, led OSSC to propose the study.

The study

The study proceeded in two phases. Phase 1 took place in a controlled laboratory environment and focused on breath hold times in cold and warm water, with and without the mask. The amount of time that participants could hold their breath in cold water was significantly less without the mask: 28 seconds compared to nearly 57 seconds on average. Evely cited the cold shock response, which includes the gasp reflex (urge to breathe), noting that these results point to the additional benefit of thermal protection that the mask provides to the facial area. (Workers flying offshore in Atlantic Canada are required to don a thermal protective helicopter transportation suit system throughout their flight, and the face and hands are the only exposed areas.)

In Phase 2, 136 participants completed 416 exercises during OSSC’s three HUET training courses (offshore survival introduction, basic survival training, and basic survival training recurrent) at the training tank at OSSC’s Foxtrap campus 30 km (18 miles) outside of St. John’s. Capable of accommodating up to 12 students, the HUET was custom-designed and built by Survival Systems Ltd. of Dartmouth, Nova Scotia, to simulate the Sikorsky S-92 helicopter. Approximately 50% of the participants were randomly selected to wear masks. The majority were working offshore at the time, ranging from caterers to ROV operators. The objectives of Phase 2 included determining:

  • The mask’s effect on the user’s stress levels during training;
  • The mask’s effect on egress time during HUET training;
  • The mask’s effect in terms of either hindering or assisting egress; and
  • The effect of training on mask donning.

Using the State-Trait Anxiety Inventory measure, it was found that there was no significant difference in the stress levels of the mask/no mask groups. Directly following the HUET exercises, anxiety decreased for all subjects. Regarding egress time, no significant difference was measured with/without the mask.

Egress performance

There were some notable differences, however, in terms of egress performance. It was observed that subjects made significantly more errors without the mask and that the errors made were of a more serious nature. In one test the subjects broke the brace position to hold the dive mask in anticipation of the helicopter inverting. A much higher percentage of the participants who were not wearing the mask broke the brace position to plug their noses – 3.8%, compared to 0.7% for those wearing masks.

One test indicated a benefit regarding vision, with 3.8% of those who were not wearing a mask being unable to locate the window that required jettisoning to exit (these subjects either had their eyes closed or were unable to see, Evely said). All of those who were wearing a mask were able to find the window. There were some reports that masks had leaked. Facial hair appeared to be the main reason for this.

The Mares dive mask that was used in the study was selected to reduce the variable of leakage. Its double skirt allowed more flexibility in getting a seal, and Evely said that the soft silicone also facilitated this. There were adjustable straps and separate lenses for each eye. Two mask sizes were used, which ensured the mask would fit a higher percentage of the population. (This is not the same mask that is carried onboard the Cougar helicopters that provide transportation to and from the Newfoundland and Labrador offshore oil fields.)

While there have been some objections to the use of the dive mask in the past, Evely said that they need to be held up to scrutiny. One concern is the fear that the individual could be thrown forward and the mask shattered, resulting in injury or fatality. She said that the now common use of four-point harnesses in place of lap belts on helicopters and training simulators has significantly reduced this risk. In addition, shatter-proof materials could be used in masks to further mitigate this risk.

One issue that was not addressed in this study is the integration of the mask with the suit. Evely said it needs to be determined whether a new mask will need to be designed for this purpose. Another area that has yet to be explored is the effect of high-impact forces on the mask. Future research would enable the team to recommend the requirements for dive mask design that are acceptable for use in helicopter underwater egress.

Evely and her colleagues at the OSSC presented the results of the first phase of the dive mask test at the International Association for Safety and Survival Training conference in St. John’s in October 2012. Greg Harvey, an OSSC instructor in basic survival training, said, “There’s a big gap out there in terms of people’s knowledge of the mask.” He pointed out that while Atlantic Canada is the only jurisdiction where dive masks are provided on helicopter flights servicing the offshore oil and gas industry, schools in other jurisdictions have been using the dive mask as a training tool.

It is anticipated that a follow-up study will be conducted to address these issues. Evely said that further research is required before an application can be made to the regulatory authorities to mandate the use of dive masks for underwater helicopter escape.