As Nitric Acid is classified as a 'Hazardous' substance, it is essential that Nitric Acid packaging is suitable to contain the material in a safe manner.? This means that? the container must be compatible with the product inside and any materials in direct contact with the substance must not be affected or have any effect on the 'Hazardous' substance.
Suitable materials for HNO3 packaging can include glass, plastic or metal for inner or single packagings, while outer packagings would include fibreboard, wood, plastic or metal.? The size of the receptacle will determine the standard of packaging to be used.? Limits are applied to Nitric Acid packaging in terms of volume (in litres) or mass (in kilogrammes).? These limits are known as 'Limited Quantities'.? Up to and including these volumes or masses, the packaging has to be suitable to contain the substance but does not have to carry the 'UN' symbol.? If these limits are exceeded, then any packaging used must be 'UN' approved and as specified in the ADR Transport Regulations (The European Agreement for Transport Regulations).
UN approved packaging is identified by a coding system which, in addition to the UN symbol, also displays references to the following:-
- the type of packaging
- the specific gravity of the substance to be contained
- the date of manufacture
- the country of manufacture
- suitability for different packing groups
There are two basic types of packaging which are used.? These are commonly referred to as:-
- stand-alone packaging
- composite packaging
'Stand-alone' packaging has the markings directly applied to the container holding the substance,? This type of packaging requires no further packaging for transport purposes, providing the containers are stowed and transported in a safe manner without loss of contents or undue movement.
'Composite' packaging is a two-part system with an 'inner' receptacle holding the substance and an 'outer' container holding the 'inner'.? An example of a type of 'composite' packaging would be a glass or plastic bottle in a fibreboard case.? The 'outer' case could be designed to hold one or several 'inners'.
Damaged packaging is not acceptable and must not be used.? Instead, it must be replaced, recycled or destroyed.? However, from an environmental perspective, it makes good sense to re-use packaging where possible, providing it is in a suitable condition.? This also makes good economic sense.
All closures used for Nitric Acid packaging must be compatible with the containers and a water-tight seal is required to avoid leaks.? Ideally, the containers should be fastened with closures tightened to a specified torque setting. UN approved packaging should always be supplied with a specification certificate giving details of material, dimensions, closures, etc.
Sizes of packaging container can vary from ampoules and vials holding milliletres up to IBC's which contain over one thousand litres of product.? Above this size, substances would generally be contained within tanks.
When filling containers, it is essential that sufficient ullage is left between the fill level and the closure to allow for movement of product during carriage.? Volatile substances such as Nitric Acid may build up pressure, particularly when contained in plastic.? This can lead to the plastic container 'ballooning' if the vapours are not allowed to escape.? Therefore vented caps shoud be used to allow for this.? However, due consideration must be given to the hazardous properties of any substances before packaging as some vapours may be harmful if inhaled.? In this case, venting would be inappropriate and alternative packaging should be used.
Metal drums may be fitted with a bottom outlet but these must always be tightened before filling to minimise the risk of leakage.? Metals drums tend to be used for 'Flammable' liquids rather than 'Corrosive' materials, which could potentially attack the drums.
Acid and alkali substances are generally contained in plastic packagings such as drums or smaller carboys.? Laboratory size packs would be containers of 5 litres or less for alkalis and mostly glass for strong acids.? More dilute acid solutions would generally be housed in plastic containers.
Outer firbeboard packaging should be sealed with an appropriate tape, usually 50mm wide and ideally strengthened.? The adhesion needs to be strong to ensure good seals along all the joins of the carton.
IBC's are available in a variety of styles and generally comprise a plastic inner surrounded by a stronger exterior of tough plastic or metal.? Where the substance to be contained is compatible, IBC's of an all metal construction can be supplied.? An example of an 'all metal' IBC might be one made of stainless steel and housed in a stainless steel frame.
Depending on the customer and the intended use of the product, it may be necessary to fit tamper-proof or child-proof closures, particularly for medicinal products or those of a 'Hazardous' nature.?? IBC's should be securely sealed with some form of tie, either plastic or metal, between the lid and body of the vessel.