Best Practice Guidelines for loading, transport, and unloading of Flexitanks
# Issue 2 – July 2023
DISCLAIMER
This document is intended for information only and sets out guidelines for the safe loading, transport, and unloading of Flexitanks. The information provided in these guidelines is offered in good faith and, while it is accurate as far as the authors are aware, no representations or warranties are made with regards to its completeness. It is not intended to be a comprehensive guide for the safe (un)loading and transport of Flexitanks. No responsibility will be assumed by Cefic in relation to the information contained in this Guideline. Each company should decide, based on their own decision-making process, to apply the guidance contained in this document, in full, partly, or to adopt other measures.
Table of Contents
- Introduction
- Objective and Scope
- Risk Assessment
- Equipment Requirements
- Operating Procedures
- Flexitank Manufacturer and Operator Qualifications
- Incident Management
- Checklists
- Agents Involved in the Flexitank Distribution Chain
- Definitions and Abbreviations
1. Introduction
A Flexitank, also known as a Flexitank system, is a soft, light bladder, fitted within a standard 20-foot dry box container (see also chapter Definitions and Abbreviations for further details). The scope of these guidelines is restricted to the use of Flexitanks for the transport of bulk non-dangerous liquid cargoes within a general-purpose (GP) 20-foot freight container. The bladder is generally intended for single use. Under the aspect of sustainability, it is important that the Flexibag system should be recyclable.
For the purpose of this guideline, a Flexitank system as described in PAS 1008 will be referred to as a Flexitank. The bladder will be referred to as the Flexibag.
Transportation in Flexitanks of bulk chemical products not classified as dangerous goods is becoming an attractive alternative to transport in ISO tank containers. In the early days, Flexitank damage resulted in leaks, loss of cargo, and subsequent clean-up activities. The root cause was typically attributed to inappropriate handling and fitting and impact forces during transport of the Flexitank. In recent years, Flexitank producers and operators have achieved major improvements in bag manufacturing, container selection criteria, as well as safe loading and unloading practices. This has led to a reduction in the number of spills and leaks. These improvements, combined with a continuous search by shippers for lower-cost options for the transport of certain types of non-dangerous cargoes, have resulted in a significant increase in the number of Flexitank movements over the last decade.
Incidents involving Flexitanks pose a higher risk to result in a loss of containment compared to tank containers. The use of Flexitanks for the carriage of non-dangerous liquid chemicals should therefore only be carried out with the appropriate equipment and following the right operating procedures.
The continuous increase in the use of Flexitanks and the importance of this intermodal transport unit make a review necessary. Certain areas of the 2018 Guideline have been updated, including: compatibility test criteria for a safe using of "Flexibag materials", scope of responsibilities of each agent of the Flexitank Supply Chain, ISO 14001 or equivalent standard for Flexibag disposal, and driver skills for road transport "leg".
2. Objective and Scope
The purpose of this document is to provide guidelines that assist chemical companies, their customers, and logistics service providers in preventing or mitigating unsafe situations in the supply chain of Flexitanks by promoting best industry practices today. These guidelines should also be taken into account in the case of customer collections.
The scope of these guidelines includes:
- Equipment selection comprising Flexitank type and its connections;
- Requirements for vendors and service providers;
- Product allowance criteria;
- Standard operating procedures;
- Incident management.
In all circumstances, the applicable national or international regulations take precedence over any recommendations made in these guidelines.
These guidelines are subject to continuous improvement and are expected to be updated on a periodic basis.
3. Risk Assessment
Flexitanks shall only be used for the transport of bulk liquids that are not classified as dangerous goods according to the provisions of the International Maritime Dangerous Goods (IMDG) Code (see also chapter Definitions and Abbreviations) of the International Maritime Organization (IMO). The IMDG Code provides a list of products classified as dangerous goods for sea transport (see also chapter 14 of the corresponding Safety Data Sheet).
In addition, a number of non-dangerous goods (not classified as dangerous for sea transport) may have certain other hazards and be regulated as a hazardous substance or mixture according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). For these goods, a risk assessment should be carried out (see decision tree below), taking into account the hazards of the product and the specific transport conditions. Based on the outcome of this risk assessment, a decision should be taken whether or not the product should be allowed for transport in Flexitanks.
Furthermore, the cargo must be compatible with the Flexibag material of construction, entirely inert with the Flexibag material, meaning it does not react with or cause any degradation to the material. Additionally, the cargo must be free from any potential risks of degradation or reaction with the Flexibag material. An evaluation of the product compatibility needs to be completed by the shipper and operator and form part of the risk assessment (see also section 4.2). The manufacturer of the Flexibag is obliged to provide compatibility information and advice.
Only products that have been assessed for risk and compatibility and have been confirmed by all parties as safe and reliable should be accepted for transport in a Flexitank. The risk assessment should take into account responsibilities for incident management.
FLEXITANK SYSTEM RISK REVIEW / CONSIDERATIONS FLOW CHART
4. Equipment Requirements
4.1 Container
Containers used for the carriage of Flexitanks should be 20ft GP containers, rated to a minimum gross mass of 30,480 kg, and conforming to the provisions of ISO 1496. The containers shall display a valid CSC plate and is recommended to be less than 5 years old.
Containers for the carriage of Flexitanks should meet the shipping line condition criteria, e.g. UCIRC (Unified Container Inspection & Repair Criteria) or IICL (Institute of International Container Lessors) and in addition meet the requirements of the latest version of the COA Code of Practice. If there is any doubt about the structural integrity of the container or its suitability for installing or transporting a Flexitank, the container should be rejected and replaced.
It is a requirement to inform the shipping line and/or the container owner when placing the order that the container is to be used for a Flexitank and to confirm the specified requirements.
4.2 Flexibag
The Flexibag shall be manufactured out of virgin, high-quality, food contact approved materials (not recycled) and shall meet the requirements of the COA Code of Practice for Flexitanks that was published on the COA site and the latest version of PAS1008. In case of multilayer Flexibags, only the inner layer (with contact to the product) must be of virgin material.
The manufacturer should be certified and listed in the COA Flexitank Quality Management List (FQML) with the status COA Member Certificate of Compliance. The minimum requirement is that the manufacturer complies with PAS1008.
The most common material used for Flexibag manufacturing is polyethylene (PE) but other materials, like PVC, can also be used. The material of construction of the Flexibag and valves etc. must be compatible with the liquid content (product to be carried) and subsequent uses of that content, like food and pharmaceuticals.
In case of signs or evidence of a technical non-conformity for PE/PP resistance in the Flexibag, some resistance tests need to be performed for the material, including tension and strength, stretch, tears, impact, homogeneity, etc. in order to verify its suitability. Standardised tests or similar methods carried out with the same materials may be checked too.
For new products, the compatibility must be tested in advance. However, when the new product has similar chemical properties to other products already being carried, the new product may be carried without compatibility testing. In addition to material compatibility, the Flexitank shall be tested in accordance with the provisions of PAS1008.
For quality reasons, criteria and methods for checking the chemical compatibility between the materials of the Flexibag, and the chemicals being transported, shall be conducted. There should be compatibility / homologation tests carried out to ensure that there is no migration, degradation, or reaction between the Flexibag materials and the chemical goods transported bearing in mind the whole transportation time.
Manufacturers of Flexibag and manufacturers of chemicals should give their approval for transporting goods in an appropriate way for the Flexitank selected for using.
The volume of the Flexitank can vary up to 24,000 l. Flexitanks have strict requirements on filling degree against its design volume. The filling degree shall be in accordance with the manufacturers’ specifications. Short load and overload out of the safe tolerance are both prohibited. The maximum loading weight should not exceed 24,000 kg.
4.2.1 Pressure Relief and Vent Valves
Flexibag may be fitted for emergency with a safety device (PRV-Pressure relief valve) instead of being intended to work in normal (un)loading condition. It is always part of the (un)loading procedure to include operations which assure avoiding overpressure and/or any operation which would trigger the PRV.
PRV could introduce potential leaking point of the Flexitank, so its use should be limited to those products that may ferment or release gas in transit. If a PRV is installed in the Flexibag for such loading/product purposes, then a risk review should be completed by the user to determine if benefit and justifies to use a Flexibag for such products.
Manual vent valves (with hose and tap) have a different design to the PRV. It is not triggered by overpressure, instead it is manual open/close to release air trapped in the Flexibag during loading. This consequence has been a typical issue for foaming product, extra air being trapped in the Flexibag. By opening the manual valve tap in the last stage of loading, the air can be released so the product can be loaded according to target weight. Also, sometimes such products, like latex, are usually sensitive to air that contributes to skinning formation while releasing air as much as possible right after loading can minimize the skinning issue. Normally the tap is closed immediately after air pressure is released.
Manual vent valves, as above mentioned, are intended to be used in normal loading operation instead of overpressure emergency in transit. Finally, they do not create an open channel to the atmosphere so the leaking risk is much lower.
4.3 Bulkheads
Use of bulkheads of adequate strength and rigidity is strongly recommended to prevent pressure on the doors. The bulkhead shall consist of highly-resistant metal or similar material and made of less number of pieces to minimise the training efforts for the people involved using bulkheads. This should also be considered for Flexitank systems designed to operate without bulkheads. Wooden bulkheads are however forbidden. The board used in the bulkhead system shall be made of material that is resistant to water and moist and not fragile which may become a sharp point if broken.
4.4 Loading Equipment
The filling process needs to be done in a controlled manner taking into account bag capacity to avoid over or underfilling. Filling with a compressor/pressure is not allowed.
4.5 Lining on Walls of the Freight Container
Each manufacturer should establish the Flexitank lining because this shall be adapted to the used containers. There are numerous types of solutions. The lining can be applied to the floor and walls of the container, it should be insulating, resistant to water and moist and shall be free of over-extensions or grazes.
5. Operating Procedures
5.1 General
Safety transport of liquid cargoes in Flexitanks includes the selection of container, mounting, quality and design of the bag, and the road transport leg of the entire Flexitank transport operation. It should be checked if the material to be carried is a non-dangerous good (see chapter 14 on SDS) and if the risk assessment has not revealed (see section 3, “Risk assessment”) any unacceptable risks or incompatibility of the product with the bag material.
Flexitank suppliers should provide a manual including the process description of the container selection, Flexibag fitting, container lining, bulkhead installation, loading, labeling, and unloading. For the loading/filling of the Flexitank, it is recommended that a trained person, responsible for, and knowledgeable about, the correct filling and handling of the Flexitank, and another person, responsible for and with expertise on the loading equipment and facility, execute and monitor together the entire loading operation. This is consistent with principles for the loading of tank trucks and tank containers, as established in the Cefic-ECTA-FECC Best Practice Guidelines for Safe (Un)Loading of Road Freight Vehicles.
A checklist for all container/Flexitank checks should be used (see section 8) and it is recommended to make pictures of the selected container, including all four sides and inside of the container, and the CSC plate. During all activities the required PPE should be used, based on the physical and chemical properties of the material to be loaded into the Flexitank.
5.2 Loading/Filling
5.2.1 Container Preparation
5.2.1.1 Visual Outside Check of the Container
The container is preferred to be less than 5 years old, should have a valid CSC plate (see section 4.1). The suitability of the combination of the Flexibag and container should be checked according to manufacturer instructions and the loading limit according to manufacturers’ specifications (see section 4, “Equipment requirements”).
A visual check of the container should be carried out to be sure that the container is structurally undamaged (see Section 4 Equipment requirements).
The exterior of the container must be free from ‘dangerous goods’ markings or markings relating to previous cargoes.
The container should have two proper operational locking bars on each door and doors must be able to be operated and secured as intended.
5.2.1.2 Visual Inside Check of the Container
The container must be free of any previous damage.
Identical corrugations must be in place over the full length and there must not be a logo panel or any flattened corrugations.
The container must be dry, rust-free, in clean condition, free from sharp edges and from residue or odors of all previous cargoes.
Lashing fittings at bottom rails and corner posts should not be damaged as they could cause punctures.
Door recesses for bulkhead fixings must be in good condition and free from dents and obstructions.
5.2.1.3 Preparation and Installation of the Flexibag
The following precautions should be taken for the preparation and installation of the Flexibag inside the container. The party who installs the Flexibag into the container should use a checklist (see chapter 8. Checklists) that includes all relevant points for a correct assembly of the Flexitank. In any case there must be good coordination between the involved parties (Loader and CTU Operator) to demonstrate that all checklists have been completed:
- The inner wall of the container must be covered with protection layers that extend to the full height of the filled Flexibag (usually approximately 2/3 of the total container height). This is a protection of the Flexibag from abrading against bare material. Usually, corrugated cardboard is used.
- During floor protection and Flexibag installation, shoes should not be worn inside the container to avoid destruction of the protection material and to guarantee a clean surface.
- During the whole transportation process, it is not allowed to physically step on the Flexibag in order not to damage the Flexibag surface (e.g., sharp items in the shoe sole).
- The Flexibag must only be fitted and positioned inside containers by specially trained personnel and placed in a position