R EFF : 106-149, 151-199, 201-299, 301-399, 35-31-00Page 1 401-499, Config-2 Aug 01/05
CES
Flight-Crew Portable Oxygen Equipment
Figure 001
R EFF : 106-149, 151-199, 201-299, 301-399, 35-31-00Page 2 401-499, Config-2 Aug 01/05
CES Operation of the hood is silently and reliably powered by the exhalation of the wearer into an oronasal mask cone located within the hood. The low moisture content of the oxygen gas generated by the KO2 bed reduces the wet bulb temperature, improving wearer comfort and controlling misting or fogging of the visor and/or glasses. The complete device is secured to the head to minimize restrictions to mobility. A neck shield extends downward from the back of the hood to protect the collar and upper shoulder area of the user from direct flame contact. A speaking diaphragm is installed in the oronasal mask cone to enhance communication.
(c)
Technical Data Breathable gas: Chemically supplied oxygen (approximately 50 liters on demand). Duration: 15 minutes to 30 minutes when used in accordance with specified work rates. Weight: 3.75 lb (1.7009 kg) Starter candle: Not less than 8 liters of oxygen within 20 seconds of initiation. Rebreathing volume: Nominal 8 liters. CO2 Concentration: Less than 4% at maximum test condition workrate. Inhaled gas temperature: Less than 40.Celsius (Wet Bulb) at nominal test condition workrate.
(d)
General Operation During the donning sequence, the chlorate candle is automatically actuated as adjustment straps are pulled to secure the oronasal mask cone against the face. Since the neckseal is already positioned, the oxygen generated by the chlorate candle will inflate the hood, providing adequate initial breathing volume, and accomplish some purging of the hood with any excess gas generation. As the wearer begins to breathe normally through the oronasal mask cone, the exhaled breath is directed through the KO2 canister, which removes water vapor and carbon dioxide and adds oxygen before the gas is returned to the interior of the hood for inhalation. This breathing cycle will continue until the KO2 bed is exhausted. Exhaustion of the bed results in a loss of active oxygen-generation capability coupled with a rapid increase in internal temperature and release of moisture through the KO2 bed. The loss of oxygen-generating capability results in a gradual reduction of the interior volume of the hood.
R EFF : 106-149, 151-199, 201-299, 301-399, 35-31-00Page 3 401-499, Config-2 Aug 01/05
CES
(e) Hood Operation (Ref. Fig. 002) The hood encloses the head of the wearer and is sealed to the wearer by the neckseal. The enclosed volume of the hood represents approximately 8 liters available rebreathing volume, or counter lung. The oronasal mask serves to direct the exhaled breath containing CO2 and water vapor back through the KO2 bed where moisture and CO2 are removed, and drier oxygen is added for return into the hood volume. Inhalation is accomplished directly from the interior of the hood through the inhalation valve located on the oronasal mask. A relief valve located at the back of the hood is used to prevent build-up of excessive pressure within the hood, and to provide emergency pressure relief in the event of a sudden reduction in cabin pressure. The chlorate starter candle installed at the bottom of the KO2 canister is designed to deliver a fixed volume of approximately 8 liters of oxygen over a short duration of less than 20 seconds. It is contained in a small stainless steel cylinder affixed to the base of the KO2 canister. The discharge is directed into the interior of the KO2 canister. The chlorate candle is initiated by a spring-loaded plunger striking a small percussion primer when the lanyard attached to the hood adjustment strap is pulled. The heat developed from the percussion primer is sufficient to start the decomposition reaction of the active NaClO3 material, producing oxygen and forming common salt (NaCl).
(2) Storage The smoke hood system is normally packaged in a two-component system consisting of a low moisture transmission aluminized vacuum-sealed bag installed in a tamper-resistant protective container. Since the active air regeneration chemical (KO2) is moisture sensitive, the primary function of the vacuum-sealed bag is to maintain an effective moisture barrier. Loss of vacuum resulting in slight inflation of the bag is an indication of loss of the moisture barrier, requiring replacement of the unit. The protective container provides a barrier to prevent accidental damage to the vacuum bag. The container is fitted with a tamper indicator that must be broken to allow access to the bag. The container additionally provides an inspection door to allow observation of the enclosed vacuum-sealed bag to verify installation and condition of the vacuum seal.
R EFF : 106-149, 151-199, 201-299, 301-399, 35-31-00Page 4 401-499, Config-2 Aug 01/05
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