Adventure Diving

Gear Service

We will meet or beat our local competitor pricing on equivalent training and equipment!

        Certified professional diving equipment service!  

     

Dive Equipment Services

 

      Adventure Diving certified technicians will keep your equipment in excellent

repair! We use all oxygen compatible repair kits and all gear is certified to use

with NITROX.

   

      Adventure Diving can perform the following diving equipment services:

 

        Regulator Annual Service

        Buoyancy Control Device Annual Service

        Hydrostatic Testing

        Cylinder Visual Inspection and Valve Services Including Visual Inspection Plus

        Dry Suit Repairs and Valve Services

        Gauge Testing

        Dive Computer Battery Repair and Maintenance

        Wet Suit Repairs

        Equipment setup and testing

        Custom Repairs and Maintenance

        SCBA Service

  

 

   

        

              

Complete cylinder service should include checking the hydro test date is within the five year span, a yearly visual inspection, oxygen cleaning, visual plus eddy current test, blow out disk replacement, valve overhaul, and proper labeling. Anything short of this is insufficient! The visual inspection checks for obvious dents, bulges, cracks, oxidation,  thread damage, and hydro test date. Oxygen cleaning removes hydrocarbons and kills bacteria the could be ingested during respiration.Thevisual plus eddy current test checks for dangerous cracks in the thread and neck area which can be compared year to year for changes.

The blow out disk can oxidize and blow out at a lower pressure than specified for the application or even during a dive! Valves should be overhauled to repair or replace worn or oxidized parts and replace lubricant for a safe dive also. Proper labeling is very important to know the date of the next hydro, visual, and gas contents.

 

Burst or blow out disk information!

Cylinders and Burst Disks
 There is a myth that leaving a SCUBA cylinder in the trunk of a car places the cylinder in serious danger of blowing a burst disk. This is not likely, especially with new equipment.  This would only happen if the burst disk is fatigued, and well out-of-spec on the low end of its rating. The purpose of the burst disk is not to protect the cylinder from solar heat in the trunk of a car. The burst disk purpose is to protect the cylinder if left unattended while filling from a running compressor that has a rating well above the cylinder rating, and possibly protecting the compressor, though most compressors have their own pressure relief valve. Burst disk are designed to burst at well above the cylinder rating - often around 40% above nominal. For a single aluminum 80 cylinder, that would be:

3000 PSI  x 1.4 = 4200 PSI.

Charles' Law states that: (Pressure x Volume)/Temperature is constant, meaning that pressure rises with temperature to keep their ratio a constant if the volume remains the same.  This can be expressed as:

P1 / T1 = P2 / T2

Many people believe that a 140 degree F trunk vs. a 100 degree F fill temperature would yield a 40 percent increase in cylinder pressure:

3000/100 = P2/140, or P2 = (3000/100) x 140 = 4200 PSI

BUT!!!..... It doesn't work that way because the pressures are relative to "absolute zero" temperature (-460 degrees F).  Degrees Rankin equal Fahrenheit degrees in size, but measured relative to absolute zero. Since the equation for Charles' Law is based on degrees Rankin, the example above is correctly calculated as follows:

3000 / (460 + 100) = P2/(460 + 140)

3000 / 560 =P2 / 600

P2= (3000 / 560) x 600 = 3215 PSI

This value is well below burst disk concerns. The burst pressure is rated at nearly 1000 PSI above the expected 215 PSI rise in a 140 degree Texas trunk in the 100 degree summer day (assumed temperature for rated pressure in the summer). If you fill the cylinder in an 80 degree room/water tank, the rise would be greater relative to the filling pressure, but well under 4200 in the example.

3000 / (460+80) = P2 / (460 + 140)

3000 / 540 =P2 / 600

P2= (3000 / 540) x 600 = 3333 PSI

This value is still only about 11% over rating, and within tank safety margins. Cylinder tip! - Store your cylinder with very low pressure (500 PSI) to keep water out and material stress low. If that isn't practical, store it full. In a house fire, the burst disk may blow from heat combined with pressure if the storage pressure is high. If the aluminum cylinder is half full, the cylinder will likely give way before the burst disk because aluminum is severely weakened by extreme heat, and the pressure rise might never reach the rated burst temperature before catastrophic failure of the cylinder.

Written by:

http://www.searover.com/rca/scuba/opinions/scuba_opn_burst_disks.shtml

Copyright © 1998 - 2006
Randall C. Allen
All rights reserved

 

References: Compressed Gas Association and several cylinder manufacturers!

 

 

Complete buoyancy control device yearly overhaul should include pressure testing the bladder, checking for leaks, cleaning the bladder inside and out with an approved cleaning agent, checking for strap and material wear, and overhaul of all inflation and dump devices. If everything is checked, overhauled, and tested, it may the be marked or tagged for return to safe service!

 

SCUBA Lessons the HARD WAY!

 

"A Bad Bargain"

By Michael Ange.

                      The deafening roar of escaping air assaulted Dan's ears as he struggled to breathe from the violently free-flowing regulator. In spite of the cascade of air, every breath was filled with water and he had to inhale cautiously just to avoid choking. To make matters worse, he couldn't see past the curtain of bubbles boiling upward and had no way to signal his buddies for help. Fighting back panic, he stole a look at his pressure gauge. The needle was steadily winding its way toward zero, and he already had less than 500psi left in his tank. Unable to control his fear any longer, Dan bolted toward the surface!

The Divers
Joy and Al were active recreational divers who convinced their friend Dan to earn his C-card and join them on their frequent dive vacations. Certified for less than a year, Dan was still accumulating his gear and as they left for a weekend island getaway, he proudly showed off his latest acquisition-a high-end regulator still in the box. Dan had purchased it at a huge savings from a web site selling discount dive equipment.

The Dive
When the divers arrived on-island, Dan borrowed some tools in order to attach an octopus and pressure gauge to his new regulator. The divers entered the water as a three-man buddy team and descended to the reef 60 feet below. The sight of a black-tip shark in the distance enthralled Dan, and when he turned back to his buddies, he noticed that they were far ahead of him. Dan dropped the last few feet to the bottom and swam quickly to catch them.

The Accident
Dan was breathing hard on his regulator when he heard a distinctive pop behind his head, followed by a deafening roar as air began to gush from his mouthpiece. There were bubbles everywhere and the free-flowing regulator was shooting air-and a generous amount of water-into Dan's mouth. Struggling not to choke, Dan looked for Joy and Al, but could see little beyond the curtain of bubbles.

As his anxiety grew, Dan's ability to deal rationally with the problem began to decay. At some point, it dawned on him that he was wasting too much time and losing air way too fast. He pulled his pressure gauge directly in front of his mask and was stunned to see his tank was nearly empty. Seized by panic, he began swimming rapidly for the surface.

The Rescue
Dan surfaced, screaming for help and struggling to stay afloat. The boat captain yelled for Dan to inflate his BC and drop his weight belt as the mate dived in and swam rapidly to the panicked diver. Grabbing Dan just as he began to sink below the surface, the mate managed to add a small quantity of air to the BC and released Dan's weight belt.

Dan was in full-scale panic, but thanks to the mate's quick action, he was no longer in danger of drowning. The mate backed away, letting Dan exhaust himself while calmly issuing reassuring commands. Slowly, Dan's panic began to recede and he dropped into a state of exhaustion, allowing the mate to safely approach and tow him back to the boat. Though shaken, Dan escaped without harm.

Analysis
As with many dive accidents, this one was set in motion long before the divers entered the water. In this case, the problem began when Dan clicked the purchase button on a web site offering "brand-new, out-of-the-box equipment" at "big savings."

Dan was very proud of his internet shopping savvy, but he failed to recognize the importance of making sure his life-support equipment was properly inspected by a qualified technician. Manufacturers produce tens of thousands of regulators each year and some will have problems. This is why dive stores are required by their dealer agreements to inspect and test each regulator before delivery to a customer. Some internet and discount venues-including the one where Dan found his great deal-do not offer these inspection services.

An inspection of Dan's regulator immediately following the accident revealed several issues. First, there were metal shavings inside the regulator's first stage, apparently left over from the manufacturing process. Under pressure, these shavings cut into the seat material causing the first stage to fail and creating the violent free flow. The technician also found a loose port plug on the regulator. The O-ring on the plug was extruded, probably as a result of the high-pressure seat failure, and was the apparent source of the water Dan inhaled during the free flow. It is unclear whether the plug was left loose in assembly or whether Dan loosened it by mistake when he attached the additional hoses. Either way, a proper inspection would have identified all of these problems and prevented this accident.

Once the accident began, Dan's buddies were nowhere near and never realized the problem until they surfaced at the end of the dive. This is a clear example of how three-man buddy teams provide only the illusion of safety unless all members of the team recognize their responsibilities.

Even with these mistakes, Dan's accident was still not life-threatening until panic took over. He had ample time and air to make a slow controlled ascent, and that is precisely what he should have done as soon as it was apparent that his buddies were unavailable. At the surface, Dan compounded his problems when he failed to get positively buoyant. Dumping his weights and inflating his BC would have helped control his panic.

Lessons for Life

  • Be frugal-not stupid. When comparing bargain-priced equipment to the gear for sale at a reputable local dive store, add the cost of setup and service to the cost of the bargain. Either way you buy, be sure a technician checks your equipment.

  • Three is a crowd. Whenever possible, only dive in two-man buddy teams. If you must dive as a buddy trio, assign specific obligations to each diver.

  • When in distress, surface-slowly and deliberately before you have to do it without control.

  • Get positive. Dump your weights and inflate your BC as soon as you have reached the surface, or even sooner if you feel you can't make it there. It doesn't hurt to practice this skill in controlled conditions before you have to do it for real.
     

  • Remember! Dan saved a few bucks by ordering his gear online, and it nearly cost him his life!

 

SDI / TDI / ERDi Top 5 Award Winning Facility

- Adventure Diving