A Breathing Apparatus Normally Known As The BA Set Or The SCBA (Self Contained Breathing Apparatus) Is An Equipment Used To Supply Fresh Air For Human Breathing When A Person Is Entering Any Space Where The Atmosphere Is suspect And May Not Support Human Life.
Such Situations Arise :
1. When Entering Into An Enclosed Space.
2. When Entering Into A Space To Fight Fire.
3. When Entering Into A Space Not Enclosed But Has Been Kept Closed For A Long Period Of Time.
4. Entering Any Other Space Where The Atmosphere Is suspect.
Breathing Apparatus Are Of Two Types :
1.The Forced Air Breathing Apparatus Which Is An Earlier Version
2.The Compressed Air Breathing Apparatus Which Is The Later Version
Give A Brief Description About The Forced Air Breathing Apparatus?
The Forced Air Breathing Apparatus May Not Be Seen Very Often Today, As Most Ships Are Equipped With Compressed Air Breathing Apparatus, But Is Mentioned Here As A Matter Of Interest.
This Apparatus Consists Of A Face Mask With An Integral Speech Diaphragm, Rubber Breathing Tube, Terylene Harness Assembly With Shackle, Hemp Covered Wire Rope Life Line, Signal Plate, Air Hose And Double Acting Foot Operated Bellows
1.Fresh Air Is Provided By The Bellows And Is Drawn From The Hose By The Wearer's Own Aspiratory Effort.
2. The Equipment Is Situated In Fresh Air, To Windward Of Entry Point.
3. An Exhaling Valve Allows Escape Of Excess And Exhaled Air.
4. The Bellows Can Be Hand, Foot Petal Or Power Operated And Should Be Situated In Fresh Air.
5. A Second Person Is Required To Operate The Bellows To Supply Air To The Wearer.
6. The Air Hose Is Usually Of Sufficient Length That The Wearer Can Reach Any Compartment With The Bellows Kept On The Open Deck Near The Compartment.
Some Of The Disadvantages Of This Apparatus Are:
1. Constant Supply Of Air Is Dependent On The Second Person.
2. Air Tubing Being Long, Has To Be Trailed, It May Get Stuck Between Ladders Or Rungs, It Restricts The Wearer In His Movements Limiting His Area Of Operation.
3. The Air Tubing May Get Cut Or Can Be Damaged Thereby Endangering The Wearer During Operation.
4. The Apparatus Is Bulky.
5. Smoke Bellows Is Not A Positive Pressure Set, Therefore If It Does Not Fit Perfect Perfectly, Contaminated Air May Enter Mask.
How To Use SCBA?
Follow The Manufacturer's Instructions For Connecting The Harness To The Cylinder And Then The Air Hose To The Face Mask.
1. Lay Down The Harness Assembly With The Pressure Regulator And The Warning Device On The Floor.
2. Open The Straps To Hold The Cylinder, So That The Back Plate Of The Harness Is Clear To Keep The Cylinder.
3. Place A Fully Charged Cylinder On The Harness Back Plate Such That The Connector Nut On The Harness Assembly Fits Into The Cylinder Head.
4. Inspect The Connector Nut To Ensure That The 'O' Ring On The Connector Nut Is Not Damaged.
5. Tighten The Connector Nut Into The Cylinder, Make It Hand Tight.
6. Place Cylinder Straps Around Cylinder, Fit The Bolts Provided On The Cylinder Strap And Tighten It. Please Note That Securing Arrangement On Different Models Of BA Sets May Be Different.
7. Adjust Shoulder Straps And Waist Belt To Their Full Extent And As Required By The Wearer.
8. Connect The Face Mask To The Connection Provided In The Harness By Means Of The Supply Hose Attached And Quick Connecting Coupling.
9.The Self Contained Breathing Apparatus Is Now Ready To Be Used.
What Checks To Be Done Before Using BA?
Checks That Have To Be Carried Out Before Using The Apparatus
1. On The Demand Valve There Is A Red Button Or A Lever To Ensure That The Mask Is Maintained Under Positive Pressure At All Times When Worn By The User. Ensure That This Lever Is Kept Off.
2. Check The Cylinder Pressure. Open The Cylinder Valve Slowly But Fully And Read Off The Pressure Gauge. Pressure Of The Cylinder Should Be No Less Than 10% Below The Filling Pressure. For Example, In Case The Filling Pressure Is 200 Bar, Then The Meter Reading Should Not Be Less Than 180 Bar. If It Is Less, Replace The Air Cylinder With A Freshly Charged Full Cylinder. Please Note, Since The Apparatus Has A Restrictor Fitted To Protect The High-pressure Hose And Gauge, It Takes Some Time Before The Pressure Gauge Shows The Full Pressure. Hence It Is Necessary To Wait About 10 - 15 Seconds Order To Fully Pressurise The System.
3. High Pressure Leak Test : Close The Main Cylinder Valve And Check For Leakage In The System. The Pressure Gauge Reading Should Not Fall By More Than 10 Bar In One Minute.
4. Check Whistle Warning Unit : Switch On The Positive Pressure Facility By Hand Slowly And Listen To The Air Flow. Keep A Watch On The Pressure Gauge. When The Pressure Gauge Shows Approximately 50 Bars (about 10 Minutes Usage Time) The Audible Alarm Will Sound. The Audible Alarm Will Continue To Sound Till The Pressure Gauge Comes To Zero.
The Above-mentioned Must Be Necessarily Carried Out Every Time Before Using The Apparatus To Ensure That The Apparatus Is In Good Working Condition.
Bhupesh Srivastava is a Marine Engineer by profession and sailing as a 3/E on FG vessels. He loves reading, writing and blogging. He loves to write about Marine Automation, MEP and Marine Auxiliary machines.
Procedures for starting, stopping and taking on load GeneratorsPrecaution Must Be Taken While Starting And Taking ....
>> READ MORE10 points you should know about EEBD/ELSAEmeregency Scape Breathing Device (EEBD) / Emergen ....
>> READ MOREFAQ Orals MEP (Auxiliary Boilers)What Would You Do If You Had A High Chloride Level ....
>> READ MOREIntroduction of new CPR Ring by MAN B&WA Number Of Incidents Came In Focous With High Top ....
>> READ MOREConsequences of Low Load Operation of Diesel GeneratorsQ. What Is A Cylinder Liner Protection Ring & What ....
>> READ MOREAll you need to know about Classification societiesWhat Do You Mean By Classification Society? ....
>> READ MORECentrifugal Pumps Vs Positive Displacement PumpsThe pumps behave very differently when considering ....
>> READ MOREMarinelookout is an intiative by seagoing Mariners to make life easy for the marine fraternity either at sea or at MMD. With Marinelookout we deals with several areas of maritime industry like - Day to day MMD oral Questions. Specific blogs inscribing the questions faced. Separate ePariksa section which prepares you for the written exams of MEO Class IV. Pre Sea Section is for the Cadets at College, which provides them the gateway to Sea. Its to help them understand the basic topics in a simplified manner. Marinelookout has a very dedicated team of young guns who are fired up to perform. We also have Chief Engineers and Masters who make us a complete organization.In the upcoming years we are going to create a marine knowledge hub over the internet. Its just a matter of time, be with us now and you can avail the fruits ever.