General usage of hoses
The choice of hose and couplings in combination with the medium and usage requirements.
- Physical effects: causing change in volume of the hose material, consequently causing a change in its characteristics i.e. hardness, tensile strength, elongation etc. (example "pop- corning" in steam hoses)
- Chemical effects: causing change in chemical construction of hose material, causing change in properties (e.g.: plasticizers or ageing-protectors are decomposed causing possible spill or leakage).
- The permitted working pressure and vacuum are not to be exceeded.
- The permitted working temperature in interdependence with the medium is not to be exceeded.
- In case of abrasion always consider wear and tear, and regular checking of the hose is required.
- While using the hoses make sure there is no dangerous electrical charge
- Hose assemblies may, in the process of use, never absorb dangerous electrical charges and where applicable the electrical resistance (measured over the hose from fitting to fitting)6may not exceed the value of 10 6Ω.
- Hoses marked with "Ω" are equipped with materials already causing conductive properties.
- Hoses marked "M" need to be secured by connecting the static-wire(s) to the fittings in a permanent way, such in order to assure conductivity.
- The selection of hose and fittings must be made in correct sizes and attuned to each other.
- Assemblies of fittings may only be executed by experts and is always subjected to prevailing directives.
- Always keep the hoses dry and clean.
- Avoid influences from radiation of Ultra Violet and sunshine.
- Store tension free and kink free.
- Avoid temperatures under -20°C and over 30°C.
- Hose-assemblies must always be installed accessible for persons, in its natural position and unobstructed.
- Take into account that hoses under vacuum suffer from decrease in length, under pressure change in length and diameter will occur (non-reinforced PVC spiral hoses may elongate till 40% of its original length when maximum working pressure is applied).
- Hose-lengths may, in essence, not be claimed on their ability of torsion, elongation and pulling strength.
- Hose lengths may not be put under torsion, compression and extension.
- Hose lengths must be protected against exterior mechanical- thermal- or chemical affection.
- When required inspect and check electrical resistance of the hose lengths.
Recording the working method in a user manual
To operate hose-lengths safely it is necessary to implement technical, personal and organisational measures for protection. Preference must be given to the technical and organisational measures. Should these not avoid all dangers, effective personal safety equipment must be provided and used.
Hose-assemblies must be inspected by an expert prior to putting into use. Regular inspections are recommended then-after (e.g. chemical hoses 1x year, steam hoses min.1x semester).
Essential details of inspections should be:
- Visual inspection of the hose:
- Sufficiently cleaned?
- Bruises, kinks, distortions
- Damage to the inner and / or outer wall
- Damage to the links
- Damage or lack of seals
Pressure test, leak proof tests:
- Holes, leaks, bumps, dents, blisters, distortions
- Inadmissible length expansion, torsion
- Leaking assembly, leaking coupling
- Testen van de elektrische geleiding
- Measuring the electrical resistance of "Ohm" and "M" hoses
Record and record the test results:
By using the above guidelines for the correct use of hoses, a longer life of the hoses is possible.
Source : BG Chemie Merkblatt T002 (ZH 1/134)