E N D
7. As for all gas installations, specific risks related to each installation have to be known.
Principal danger sources about hydrogen plants are :
Gas inflammation in case of excess of warmth, sparks or flame
Risk of an « explosive » atmosphere in case of a hydrogen gas concentration higher than 4%
Gas auto ignition risk in case of a temperature higher than 500°C
Leakage risk due to the high fluidity of hydrogen gas and the difficulty of its detection
In case of inflammation, hydrogen gas is odorless, colorless and its flame is invisible.
8. As for all dangerous gas, it is absolutely necessary to stay extremely vigilant during the use of hydrogen gas.
Even if all employees in charge of the hydrogen plant are informed about the risks due to the hydrogen gas, employees become generally less vigilant after several years of experiment. This is due to a too big trust in the use of hydrogen gas and that trust is increasing with years.
The direct consequence of this kind of comportment brings harmful effects on the safety measures and on the conditions of hydrogen use, for example :
-Risk to forget to wear antistatic clothes
-Risk to forget to switch off its mobile phone during the filling of a balloon
-Risk to open brutally or too quickly the hydrogen cock of the draw off panel
-Risk to increase the hydrogen pressure of the draw off panel in order to « accelerate » the filling of the balloon,
-Lack of vigilance :
.During the hydrogen production (lack of daily verifications on the plant)
.Where the balloon is filled
9. It is imperative to respect the following safety instructions:
It is forbidden to smoke or to bring in fire under whatsoever form near the hydrogen production plant
The use of mobile phones is forbidden during the filling of a balloon
Eliminate all risks of sparks emission due to static electricity (friction of the balloon on a wall, brutal opening of the draw off panel cock, filling pressure too high) by connecting systematically all the metallic parts of the building to the ground, plus the filling table and the filling mantle (if this one is metallic)
Eliminate all the clothes able to create static electricity (Nylon, synthetic…). Wear if possible pure cotton clothes.
Check the presence of chalk in the balloon (inside and outside) before using it (chalk is an antistatic agent)
The filling pressure of a sounding balloon shall not exceed 2 bars
The balloon filling phase has to be done on a filling table in order to avoid all risks of friction
10. STORAGE OF THE BALLOONS
In order to avoid an artificial ageing of the balloons that could bring a loss of elasticity or a loss of tightness, and then some balloons bursting or some gas leakages, following measures must be taken:
The balloons must be preserved inside their origin packing, in a dark room having a temperature between 10 and 20° C and a relative moisture close to 60%.In the worst case, the temperature of the room should not reach 35 ° C.
The balloons must be classified in the order of their manufacturing date to always use the older one first.
FILLING OF THE BALLOONS
Check the presence of chalk in the balloon (inside and outside) before using it (chalk is an antistatic agent)
The balloon filling phase has to be done on a filling table in order to avoid all risks of friction
The filling pressure of a sounding balloon shall not exceed 2 bars
The filling of the balloon has to be done slowly in order to avoid risk of hydrogen inflammation due to the static electricity created by the friction of the gas between the chalk particles.
The filling of the balloon has to be done 15mn before launching it. When the balloon is filled, avoid to expose it to sunlight.
In dry areas, it is highly recommended to connect the filling cock to the ground.
11. Periodical pressure proof tests every 5 years at 1.5 time the service pressure.
The proof test has to be witnessed by an expert from the competent National Department.
Proof test certificate shall be issued after the stamping of the cell.
Proof test has to be performed with a hydraulic pump.
Proof test has to be made in case of visible defects on the cell such as :
Notch or groove 5% deeper than the thickness of the cell,
Lamination (fold, overlap, entrapment, flaking of the metal),
Punch marks, collar not fixed, Grinding recess or suspect stain.
Systematic reject has to be decided in case of visible defects on the cell such as :
Projection on the surface of the cell visible to the naked eye,
Dent greater than 0.5% of the outside diameter of the cell,
Crack or tearing of metal,
Damage due to fire,
Arcing or blow torch damage.
Systematic reject of the cylinders has to be decided after 15 years of operation.