psdarchives.aganoseblocks

AGA nose blocks

8-16-02

ANY IDEAS ON HOW TO KEEP NOSE BLOCKS FROM COMMING DISLODGE FROM AGA MASK???
CHANGING FROM MASK TO BACK UP REG(PONY) WE SOMETIMES LOSE THE BLOCK FROM
MASK. IN POOL NO PROBLEM. LOST ONE IN DELAWARE RIVER. YES, BUTCH AND ANDREA
IT IS GOOD TRAINING TO FIND THE NOSE BLOCK WE WILL WORK ON IT! STILL WOULD
LIKE TO KNOW IF YOU HAVE ANY IDEAS.
BOB DANTINNE
EASTON FIRE DEPARTMENT
EASTON,PA

8-23-02

WHAT HAPPEN TO MY QUESTION ON KEEPING NOSE PIECE IN AGA MASK? WE ARE TRAINING
ON CHANGING FROM MASK TO BACK UP REG. PONY TANK. SOMETIMES THE NOSE BLOCK
FALLS OUT THE MEN DONT SEE IT TILL ITS GONE!!! WE HAVE FOUND 2 LOST ONE! ANY
IDEAS?? WERE JUST GETTING STARTED AND USING LGS TECHNIQUES, OR SKILLS.
WE ALWAYS START ARE DIVES ON BACK UP REGULATORS AND DON AGAS UNDER WATER TO
START DIVE.

LT DANTINNE EASTON FIRE DEPARTMENT, EASTON, PA

8-23-02

Does everyone have their own AGA mask? If so you could use a small nylon tie. If not, you would have to cut the nylon tie every time you needed to adjust the nose piece.

Jim Anderson
Washington Co. Water Recovery Unit
Stilwater Minnesota

8-24-02

During my last conversation with Tim Chapman of OTS (Ocean Technology
Systems),if you don the AGA mask underwater you can perforate the membrane
that protects the communications microphone in the AGA mask.

I take either you guys do not use comms on the mask or you have not yet
experienced this problem?

Detective Estevan Martinez
Los Angeles County Sheriff's Department Dive Team

8-24-02

After losing 2 push pads myself (from practice removing
and replacing), I have been keeping mine from falling
out with a 1/2 width piece of duct tape threaded coming
over the top of the push-pad, then down to the groove
and fastened overlapping on both sides.
Guess I'll be using a nylon tie from now on.
Why didn't I think of that? Thanks Jim.

The duct tape idea may not look like much, but it is
more durable than it looks and may not be as much effort
as using a nylon tie, if they need to be moved
frequently.

Stu Weg

8-25-02

Estevan,
Please elaborate on this, I'm not sure what you mean by perforating the
membrane? We practice donning and doffing our AGAs then switching to our
pony regs, switching to the contingency bottle, taking the backup divers
pony, etc.
kv
Allentown Fire Dept.
Underwater Recovery Team

8-25-02

KV It is my understanding thru OTS that once you are under at any depth you may remove the mask and no damage will be done to the mic. We also practice all the time and in seven years with the comm units we have had to replace one once (2002). I understand " if I heard him right" it is not recommended to don the mask at depth, that is when the damage occurs?? Anyone else hear this ?

S.O.
Ct. vol. fire dive team

8-25-02

Yes. The microphone contains a semi-permeable membrane that lets air in,
but keeps water out. In the owner's manual it states:

"Getting the microphone wet will not harm the microphone. However, the
microphone element will only withstand an 8 to 10 foot depth/pressure
differential. What this means is that if you removed your diving FFM at
the back of the boat and got the microphone wet, nothing would happen.
However, if you let the FFM with element drop more than 8 to 10 feet, the
pressure could and most likely will damage the microphone element. In
tests we have taken the FFM off at 30 feet and replaced it (still at 30
feet) without any problem. If you took the FFM off at 30 feet and dropped
down to 40 feet, the pressure difference would damage the microphone."

Jeff Tibbitts
Asst. Water Team Leader
Davis County Sheriff's Search & Rescue

8-25-02

A small zip tie around the wire retainer and through the nose block will
keep the nose block in the mask and you can still adjust the block for
different divers.
Jay Kelley
Dive Team Coordinator
Sylvania Township U/W SART

8-26-02

We have been using a wire tie to hold in the AGA nose blocks for the last 2 years with great success. If you simply do not pull the tie tight you can still adjust the nose block for different divers. By cutting off the excess tie once it is installed you prevent the inadvertant tightening of the tie. Run the tie through the nose block and around the wire mounting point and leave the excess down low. Do not run the tie around the whole block or you will have to tighten it down to keep the block in place and will also have a hard plastic strip pushing against your nose when using the mask. Capt Miles Schlichte, Gloucester MA FD, Cape Ann Dive Team Divemaster

8-26-02

The warning we received from OTS was if we practice removing the AGA mask
while underwater we risk the possibility of rupturing the elastic protection
which cover the inside of the microphone. I hope that clears up any
confusion.

Estevan Martinez
Los Angeles County Sheriff's Dive Team

8-26-02

The membrane is a component of the microphone in the FFM. Since there
are several types of mic. out there you may or may not have this
concern. The benefit of the membrane -sometimes refered to as a hot
mike- is they are not as limiting on depth as some others -some ceramic
types- and they do a good job with sound transmission. If you have this
type comm. unit attached to your AGA and take off the mask under water
it is O.K.. It has equalized in air before being surrounded by water.

Now breath off a pony/octo/backup reg. and take the mask down to say 30
feet and then practice donning. It tries to eqaullize with the medium
around it (water). Water does not permeate the memberane as easily as
air. This can rip the membrane or crush components of the mic.

Surfacing with the FFM is less of a problem. The air can escape the
membrane as it expands. However, it can still rip on a rapid asent or
with prolonged exposure.

Sincerely
Don Alan Ruschak, Mon Valley Divers
Belle Vernon, PA

8-26-02

This message from Tim Chapman at Ocean Technology Systems (OTS) should
clarify the OTS ME-16 Mic concerns.

safe diving

David Holland
Lieutenant (Navy) Retired

----- Original Message -----
From: "Tim Chapman"
To: "David Holland"
Sent: Monday, August 26, 2002 10:31 AM
Subject: RE: OTS ME-16 Hot Mic PROBLEMS?

David,
Thank you for the email. By explaining how it works, you will understand
its characteristics.
The mic is truly noise canceling. This is a very similar mic that is used
with fighter pilots and helicopters where there is tremendous ambient noise.
The mic cancels the noise by having both sides open. The theory is that
the ambient noise hits both sides of the mic at about the same time thus
canceling itself out. As with pilots, the mic must be positioned less than
1/4" from the lips in order to operate at it highest performance level.
Since the mic is open from both sides there is an airspace in the center.
As you know, this airspace must equalize during decent and ascent. The mic
is equipped with a Hydrophobic membrane that allows air molecules (500 times
small than water) to pass but not water. This membrane is what makes the mic
waterproof.
You can go to any depth and remove the mask with no problem. You can even
go to the surface with the mask by your side (air will be escaping as you
ascend). You can take the mask off at the back of the boat and let it hang
in the water. You can clean the mask by dunking or with a low pressure water
hose.
The only thing you cannot do with the mask is leave it hang by your side
(in a water space) and dive deeper than a 12 fsw pressure differential. If
you do, it will squeeze the mic and cause a rupture in the membrane. The mic
will flood and eventually go out.
You also do not want to leave the mic sitting in the water for more than
ten minutes. It has the potential to saturate the membrane. If you dive the
mask with a saturated membrane, it will also squeeze the mic.
It is waterproof, with a couple of small limitations.
I hope this answered your question.

Ocean Technology Systems
Tim D. Chapman Sales and Service

Back to PSD archives index page

Lifeguard Systems, Inc. Box 594 Shokan, NY 12481

Phone: 845-657-5544

Fax: 845-657-5549