Cylinder, Fuel: Inspection
Before removing cylinders from cylinder carrier, note and mark cylinder position in relation to cylinder carrier. Also note horizontal/vertical positions of each fuel control valve. This must be done in order to install each cylinder fuel control valve back to its original horizontal position.
It is highly recommended when moving or transporting the CNG cylinder tanks that they are covered with a blanket to avoid scratching or damaging the tanks.
NEVER STORE A CNG VEHICLE OR CYLINDER TANK UNATTENDED IN A FACILITY NOT SPECIFICALLY DESIGNED FOR THE STORAGE OF NATURAL GAS.
Extreme care must be taken when servicing the CNG tank. Any type of minor damage to the CNG tank (for example, a.025 in nick, scratch or dent) can render the CNG tank unusable. Any damage, regardless of how minor, requires the tank to be officially inspected and re-certified. Before working around the CNG tank perform a visual inspection to ensure no damage is present, if any damage is discovered, do not service this vehicle until a certified Inspector can certify that the CNG tank is safe.
- The inspection of the containers must be done according to the procedures provided in CGA C-6.4 -2007. The inspection shall be carried out by a qualified container inspector recognized by the Authority having jurisdiction, as defined in Section 5 of CGA C-6.4 and with the equipment defined in Section 6 of CGA C-6.4.
- The container external surface must be clean for an effective inspection (see Section 7 of CGA C-6.4 -2007). If this is not the case, the container must be cleaned with a water - based detergent. The use of abrasives and/or solvents should be avoided. If protective cover materials (stone shields and other protective covers) prevent an effective inspection, they must be removed prior to inspection.
- Each container shall be visually inspected for external damage and deterioration on the whole external surface, including under the support straps.
- To properly examine the external surface of the container a light source capable of illuminating all surfaces should be used. The decision about the necessity to un-install the containers for inspection is up to the qualified inspector and under his complete responsibility on the basis of visual damage or unless deteriorations noted on the exposed container.
- Each container shall be visually inspected at least every 36 months or every 36.000 miles whichever comes first. Special inspection shall be performed if exists the conditions defined in Section 7 of CGA C-6.4 -2007 (Accidents and overheat, Chemical damages and over pressurization, Unusual behavior, Re-installation).
- Visual examination of the surface is made to detect container damage or evidence of potential damage like corrosion, cuts, scratches, gouges, fractures, material loss/removal, discoloration of the container surface (soot, charring, chemical attack, etc.), evidence of impact or accidents, and deterioration of the surface.
Damage Definition Decision Accept Reject Marking and
LabellingStamped and attached information Required information are present and legible Mandatory information (see 14.1.1 of ANSI NGV2-2007) are not legible.
See also 2.8.Cuts
Scratches
GougesA sharp impression where material has been removed or redistributed, including line corrosion where pits are connected or closer than one pit width from each other When depth of damage is less than or equal to 0.25 mm When depth of damage is greater than 0.25 mm Abrasion An area that is scuffed or worn
thinner by rubbing or scrapingWhen depth of damage is less
than or equal to 0.25 mmWhen depth of damage is greater than 0.25 mm Gas leakage Loss of content through a defect None detected Any type of leakage Bulge Visible swelling of container None Any visible or detectable Chemical attack Container is subjected to chemical that
dissolves or destroys the materialCleans off, no residue and the chemical is known not to affect container materials Permanent discoloration, loss/disruption of material, chemical is known to affect container materials; can't determine if materials have been affected Corrosion, pits A hole caused by a chemical, oxidation or rusting of material When depth of the pit is less than or equal to 0.25 mm When depth is greater than 0.25 mm Corrosion, line A series of corrosion pits connected in a narrow band such that the distance between pits is greater than one pit width. When depth of damage is less than or equal to 0.25 mm When the depth of damage is greater than 0.25mm Dents A depression in the container that has
neither penetrated nor removed
materialDents less than 1.6 mm deep and larger than 50 mm in diameter/length Dents 1.6 mm or more deep, or the largest diameter / length is less than 50 mm (regardless of dent depth), or both conditions exist - Containers that have been involved in accident, which may have damaged the container, or containers with known or suspected damage shall be depressurized prior to examination (see 7.3.3 C of CGA C-6.4 -2007).
- The only allowable repair is the paint repair (touch up) that shall be done after the necessary preparation.
The touch up must be done with 2 layers of paint for a minimum total thickness of 70m using a first layer, zinc rich primer. The second layer, polyurethane or epoxy paint.
- Containers without labels containing mandatory information, or with labels containing mandatory information which is illegible in any way, shall be removed from service. If the container can be positively identified by manufacturer and serial number, a replacement label supplied by the manufacturer may be applied to the container, and it may remain in service.
- Containers having damages accepted or repaired must be monitored at every periodic inspection in order to detect if the dimensions are increasing. Should defect dimensions increase the container shall be scrapped.
- This document cannot be used as a guideline for maintenance or repair of the containers by anyone who is not a qualified inspector appointed by the Authority having jurisdiction.
- It must be assumed that abnormal or unusual circumstances suggest further requirements or additional procedures.