OCENCO M-20 User manual

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Ocenco Incorporated
M-20
Self Contained Self Rescuer
Instruction Manual
Manual No. N22069
Revision A, ECN 3071

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Contents:
1. Introduction
2. Description of the M-20
2.1 Classification
2.2 Limitations
2.3 Components
2.4 Theory of Operation
2.5 Specifications
3. M-20 Care and Maintenance
3.1 How to Care for the M-20
3.2 How to Inspect the M-20
4. Donning Instructions
4.1 When to use the M-20
4.2 How to use the M-20
4.3 Transition from the M-20 to the EBA 6.5.

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1. Introduction
The M-20 was designed with two primary objectives, reliability and ease of use. The
M-20 is the easiest of all self-rescuers to use. Six simple steps (see section 5.4) and
these six steps should be practiced over and over by the trainees until it becomes
second nature.
Inquiries regarding Ocenco Breathing Devices should be directed to:
Ocenco Incorporated
LakeView Corporate Park
10225-82nd Avenue
Pleasant Prairie, WI 53158
U.S.A.
Telephone: [phone]
Facsimile: [phone]
E-mail: sal[email protected]

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2. Description of the M-20
2.1 Classification
The Ocenco M-20 is a compressed oxygen, self-contained escape breathing
apparatus. Self-contained means the M-20 supplies breathable air independent of the
surrounding atmosphere. The M-20 will provide breathable air to a person escaping
from an area of toxic gas or oxygen deficiency.
2.2 Limitations
2.2.1 Escape Breathing Apparatus
All self-rescuers, including the M-20, are considered escape breathing
apparatus. Escape breathing apparatus should not be used to actively fight
fires or intentionally enter toxic atmosphere unless it is necessary to pass
through a toxic atmosphere to escape.
2.2.2 Physical Exertion
All breathing apparatus, including self-rescuers, place some limited amount
of stress on the user due to either the weight of the unit, increased
breathing resistance or an increase in temperature of the inhaled air. For
this reason it is always advisable to limit the level of physical exertion, if
possible, while wearing any self rescuer.
2.2.3 Duration
The M-20 is approved jointly in the United States by the National Institute of
Occupational Safety and Health (NIOSH) and the Mine Safety and Health
Administration (MSHA) for a duration of 10 minutes. The duration of all self-
rescuers can vary depending on the user’s oxygen consumption rate. Five
factors affect the user’s oxygen consumption rate:
1.) The amount of work required to escape affects the duration.
Low ceilings, steep inclines and irregular floors increase the
work required to escape. Less work results in greater duration.
2.) The Physical condition or “fitness”of the user affects the
duration. A high heart rate, old age, and high percent of body
fat decrease the fitness of the subject. The more fit the user,
the greater the duration.
3.) Regardless of the “fitness”of the user, the amount of oxygen
required in proportional to the user’s weight. The less the user
weighs, the greater the duration.
4.) The user’s breathing rate affects the duration. The rate can be
increased by excitement and fear. The lower the breathing rate,
the greater the duration.
5.) The degree of training and familiarity can affect the duration.
The more training and experience the subject has with self-
rescuers, the more his breathing will be calm and controlled. If a
subject is familiar with a particular escape way it may improve
the mechanics of his escape. The greater the training and
familiarity, the greater the duration.

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2.3 Components
The M-20 consists of four main assemblies: the cover, the base, the latch and the
breathing Assembly. In the description of these assemblies the component names
are in UPPERCASE letters.
2.3.1 COVER Assembly
The COVER has an integral yellow TAB which, when lifted, releases any
vacuum developed due to the change in atmospheric pressure from the
surface to underground. Two cover overcases are affixed to the cover to
provide protection from shock and vibration.
2.3.2 BASE Assembly
The clear BASE has integral belt loops and a base overcase that is affixed
to the bottom of the base to provide protection from shock and vibration.
2.3.3 LATCH Assembly
The stainless steel LATCH band and stainless steel S-HOOK attach to
opposite sides of the BASE and clamp the COVER to the BASE. The S-
HOOK attaches to the user side of the BASE.
The LATCH band is released by raising the yellow lever on the LATCH
band. After the lever is raised, the COVER can be separated from the
BASE. The BASE stays attached to the user’s belt, and the COVER is
discarded. The yellow nylon NECK STRAP is exposed after the COVER is
removed.
The yellow lever holds a tamper ball that falls away when the lever is lifted.

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M-20 Case
1. Cover
2. Overcase Cover
3. Latch Band
4. Base
5. Overcase Base
6. S-Hook
7. Tamper Ball
8. Lever
5
4
231
1
7
3
2
5
4
8
6

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2.3.4 BREATHING ASSEMBLY
1. Noseclip: the Noseclip is attached to the Mouthpiece. The yellow pads
on the Noseclip are made of high quality natural rubber to grip the nose.
2. Mouthpiece: the yellow Mouthpiece is molded of high strength silicone
rubber. The Mouthpiece is placed in the mouth where the flange on the
Mouthpiece seals in front of the gums and the stops on the Mouthpiece
keep the mouth slightly open.
3. Neck Strap: pulling upwards on the yellow Neck Strap, disconnects the
Activation Cable from the Oxygen Controller. This action starts the flow
of oxygen into the Breathing Bag.
4. Neck Strap Ring: pulling upward on the Neck Strap Ring, shortens the
Neck Strap. It is particularly helpful to shorten the Neck Strap in
crawling situations.
5. Cylinder: the stainless steel Cylinder is of single piece construction with
no welds or joints of any kind. All of the oxygen supplied to the user is
USP grade compressed oxygen.
6. Oxygen Controller: the Oxygen Controller starts the flow of oxygen into
the Breathing Bag and automatically increases the oxygen flow during
high work rates.
7. Gauge: the Gauge indicates the amount of oxygen in the Cylinder. The
green zone on the Gauge indicates the Cylinder is full of oxygen. The
red zone indicates the Cylinder is low on oxygen and should be
removed from service.
8. Activation Cable: the stainless steel Activation Cable is attached to the
oxygen Controller and permanently attached to the inside of the Base.
Pulling the M-20 out of its Base releases the Activation Cable from the
Oxygen Controller and starts the flow of oxygen into the Breathing Bag.
9. Scrubber: the Scrubber is a chamber of Lithium Hydroxide that “scrubs”
or removes the carbon dioxide from the exhaled air.
10. Breathing Bag: the orange Breathing Bag is a 6.5 liter reservoir that
receives oxygen from the Oxygen Controller and exhaled air from the
Scrubber.
11. Relief Valve: the Relief Valve is a one-way valve that allows any
excess air in the Breathing Bag to escape. The Relief Valve limits the
pressure on the lungs during exhalation. The Relief Valve is located in
the middle of the Breathing Bag.
12. Information Label: contains unit serial number, manufacturing date,
carry date, and store date.

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M-20 Breathing Assembly
3
4
11
10
1
2
5
9
12
6
7
8
1. Noseclip (yellow)
2. Mouthpiece (yellow)
3. Neck Strap (yellow)
4. Neck Strap O-ring
5. Cylinder
6. Oxygen Controller
7. Gauge
8. Activation Cable
9. Scrubber
10. Breathing Bag
11. Relief Valve
12. Information Label

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2.4 Theory of Operation
1.) When the Neck Strap is pulled from the Base, the oxygen valve is activated.
Oxygen continuously flows from the cylinder to the Breathing Bag at a rate if
1.5 liters per minute.
2.) During the first inhalation, and when the Bag flattens, the Demand Regulator is
activated and increases the oxygen flow from 1.5 liters per minute up to as
much as 100 liters per minute.
3.) During inhalation, oxygen is pulled from the bag through the Scrubber and into
the Mouthpiece.
4.) During exhalation, carbon dioxide laden air is exhaled into the Mouthpiece
through the Scrubber and into the Breathing Bag. During inhalation and
exhalation, the carbon dioxide is being absorbed by the Lithium Hydroxide
scrubber.
5.) Sometimes during low work rates, the oxygen controller will supply more
oxygen than the user can consume and excess gas exits the Relief Valve.
The starting of the oxygen flow, the increased flow rate during high work rates
and the occasional exhausting of gas through the Relief Valve all occur
automatically, the user needs only to breathe.
2.5 Specifications
Duration: 10 minutes, NIOSH / MSHA
Dimensions: 3.0 x 6.5 x 7.2 (in)
7.6 x 16.5 x 18.3 (cm)
Weight of breathing apparatus: 2.0 lbs (0.9 kg)
Weight of breathing apparatus with case: 3.30 lbs (1.5 kg)
Minimum storage temperature: 10 degrees F (-12º C)
Maximum storage temperature: 140 degrees F (60º C)
Storage at temperatures above 140 degrees F (60º C) for short periods will not
adversely affect the M-20. In an emergency, don the M-20 regardless of
temperature.
Scrubber life is limited to one escape event or one oxygen charge
Mandatory factory service is required after 10 years if stored and 5 years if
M-20 is carried. End of service life is 15 years.

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M-20 Theory of Operation
3
2
4
5
1
1. Constant Flow of Oxygen
2. Demand Flow of Oxygen
3. Inhalation
4. Exhalation
5. Relief Valve Exhaust