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This document is meant to ensure that users of flexible, elastic tubes
made of rubber or plastic materials can obtain optimum duration, taking
into account different conditions of use.
PURPOSEAND FIELD OF APPLICATION
This document provides recommendations for users of rubber or plastic
flexible tubes that facilitate maintaining these articles in conditions similar
to those existing when they were supplied after they begin operation, and
to obtain an optimum duration of service life taking into account these
conditions of use.
This Guide to Good Practices includes two parts:
PARTA: GENERAL RECOMMENDATIONS
Section 1- Criteria for choice of tube
Section 2- Storage conditions
Section 3- Rules for use and maintenance
PART B: SUPPLEMENTARY RECOMMENDATIONS FOR SPECIFIC
APPLICATIONS
Section 1- Steam
Section 2- Food and food products
Section 3- Abrasive products
Section 4- Corrosive and aggressive products
Section 5- Inflammable products
PART A: GENERAL RECOMMENDATIONS
I CRITERIA FOR CHOICE OF TUBE
I.1 In order to choose a flexible tube that is suitable for
a specific use, the following points should be taken into
account:
I.1.1 Pressure- Negative Pressure
- Operating pressure and negative pressure values.
-Value of possible overloads (hammering).
I.1.2. Products transported
Form: liquid,gas,or solid. In solids:granulated,density,performance of solid
product transported, type, speed of passage, and flow volume transported.
- Frequency of use.
-Type, designation, concentration, operating temperature.
I.1.3. Environment
- Location of use, ambient temperature, hygrometric grade, possible
exposure to atmospheric agents or ozone.
- Products that may come into contact with the end of the flexible tube.
I.1.4. Mechanical limitations
- Minimum bending radius for operation.
- Possible limitations in terms of traction, torsion, flexion, vibration, or
compression.
- Risk of shock, abrasion, corrosion.
- Operating position: on the floor, hanging, or submerged.
I.1.5. Connection used or planned
- Connection: type, size, and type of thread.
- Manifolds: outer and inner diameter.
- Length of adjustment.
-Type and size of bands.
-Type of outer fastening.
I.1.6. Specific Conditions
Users to choose flexible tubes that comply with the standards in their
country, whenever such standards have been established within the
planned field of application.
- Requirements for specific markings.
- Application of regulations, standards, or specifications in force.
II STORAGE CONDITIONS
II.1 General
Since flexible tubes are exposed to different factors during the period of
use, they undergo changes to their physical properties. Therefore, when
the time comes to begin operation, they may not be in suitable condition.
The general storage conditions required to prevent deterioration of the
products stored are described in the following:
II.2 Duration of Storage
Whenever possible, the duration of storage period should be reduced; for
such purposes, it is essential to ensure rotation of stocks based on “first
in, first out” criteria. When prolonged storage is required, for periods such
as one year, an in-depth examination of the product must be performed
before beginning operation.
II.3 Temperatures and Humidity
Whenever possible, the storage temperature should range between 0ºC/
32ºF and 35ºC/ 95ºF (optimum temperature 15ºC/ 59ºF). The relative
humidity should not be above 65%.
II.4 Light
The articles should be stored in dark premises, protected from sunlight
and intense artificial lighting. If there are windows or glass openings in the
storage premises, these should be covered with red, orange, or white
paint.
II.5 Ozone
Due to the harmful effects of ozone on rubber articles, there should not
be any materials in the storage areas that can produce ozone, such as
mercury vapor lamps or tubes, high voltage electrical equipment, electrical
motors, or other materials that may cause sparks or electrical discharges.
II.6 Environment
Tubes and flexible tubes should not come into contact with products nor
be exposed to any vapors such as solvents, fuel, oil, grease, volatile
components, acid, disinfectants, etc. Moreover, materials such as copper,
iron, or manganese cause harmful effects for some rubber blends.
II.7 Source of heat
There should be sufficient distance between the sources of heat (heating
devices, for example) and the articles stored so that it will remain within
the temperature limits defined in paragraph 2.3. If this is not possible, a
heat shield should be used.
II.8 Electrical or magnetic field
Variations in the electrical or magnetic field in the storage premises should
be prevented, since this may lead to current in the metal fittings which
would be heated. Such fields can be caused by high voltage power lines
or high frequency generators.
II.9 Storage Conditions
Flexible tubes should be stored without limitations, elongation, or
excessive deformation.
Any contact with sharp or cutting material or objects should be
prevented.They should be stored on dry surfaces and,whenever possible,
storage compartments should be provided. The flexible tubes wound up
in a crown shape should be stored flat and preferable not stacked on top
of one another. If this cannot be avoided, the height of the piles should be
limited to ensure there are not any permanent deformations in the
articles located on the lower part. Place the heavier articles in the lower
area and reserve the higher area for the lighter articles. The winding
should be at least equal to the minimum bending radius specified by the
manufacturer or the product standard. Hanging the crowns on spikes or
hooks is not recommended. Tubes that are supplied in straight lengths
should be stored flat and without folds.
II.10 Rodents
The flexible tubes should be protected from rodents. If there is any risk,
the appropriate precautions should be taken.
II.11 Release from warehouse
Precautions must be taken to ensure that the tubes requested are in
flawless condition and suitable for the planned use. Therefore,
identification of the different tubes stored is essential. Moreover, in
specific cases in which flexible tubes have been stored for extended
periods of time, satisfactory adjustment of the metal fittings must be
verified.
II.12 Return to the warehouse
Before returning them to the warehouse, the tubes that are taken out of
service should be emptied of the substances they have conveyed. Special
care should be taken if the tubes have transported chemical products,
explosives, inflammable, or corrosive products. After cleaning, prior to
storage, the satisfactory condition and fitness of the tubes must be verified
in order to ensure future use.
II.13 Cleaning
Cleaning with brushes, sponges, or baizes should be performed with soap
and water or detergents made from surfactant products. Metal brushes,