The careful disposal of chemicals

The disposal of waste chemicals is subject to stringent regulations and needs careful consideration. Chris Ricketts, an expert in drainage, discusses the unique solutions that these specialist environments demand.

As with any design, build, refurbishment, or maintenance contract, specifying a system that delivers efficiency and value whilst meeting legal requirements can be a complicated process. When it comes to the development of chemical drainage systems, the priority needs to be selecting a material which ensures safe disposal. Compromising of just one element could mean that the system fails, budgets are exceeded, or legal standards are not met. More importantly, it could also pose a risk to the health of students or employees in laboratories, research facilities, schools, universities and hospitals.

This specific and potentially dangerous type of waste demands a piping material with a unique set of characteristics. The first consideration must be the volume and type of chemicals that will be passing through the system - this could be anything from acids, solvents and detergents through to radioactive waste. The corrosive and hazardous nature of the chemical in addition to the temperature at which it needs to be disposed of must also be determined.

Good practice

Asking these questions at the initial stage is good practice and ensures that the best possible solution is put in place. Again, these steps are vital when working with potentially harmful chemicals but in the long term they can also help to avoid unnecessary repairs and maintenance.

Plastic chemical drainage systems have advanced greatly in recent years and now offer diverse, complete solutions, which has resulted in them becoming a popular choice for specifiers and contractors. As with all types of material, plastics have differing standards and performance benefits.

For example, the disposal of detergents (including non-ionic detergents) can affect certain types of plastic when under distress.

Crystalline polymer materials, such as Vulcathene from Durapipe UK, offer high resistance to attack and would therefore be more suitable than amorphous polymers, including PVC-U, PVC-C and ABS, which can be softened and in some cases result in stress cracking.

Despite plastics taking market share, borosilicate glass is also commonly seen in this type of application; although its price often means that it is not used for whole systems. Both chemical and heat resistant, borosilicate glass is ideal for components such as bottle traps and dilution/recovery vessels. These strengths in addition to its ability to withstand strong chemical solutions mean it is often used in place of cast iron that has a tendency to corrode. However, borosilicate glass does have weaknesses, including its fragility, which makes it difficult to handle.

As well as making sure the chosen material is fit for purpose, the ideal chemical drainage system must offer versatility for all parties. This means a quick and easy installation, resulting in a secure system that keeps site costs to a minimum.

For the specifier, the solution needs to offer a comprehensive range of pipe fittings and additional items such as wastes, sinks, drip cups, anti-siphon traps and dilution vessels. If these form part of a maintenance system with demountable joints, it can be altered without damage to the original design. This means that any maintenance or requirement to expand can be done without further cost.

In addition to choosing the right material, regulations and legal requirements always need to be met. Although there are guidelines for laboratory users to follow in terms of what can and cannot be disposed of down a sink, there are currently no specific British or CEN Standards for the performance of a chemical waste drainage system while standards relating to domestic waste are not valid.

Technical guidance

So, those requiring technical guidance should look for systems that offer assurances in the form of independent testing and approvals by bodies such as the BBA (British Board of Agreement).

Ultimately, the disposal of chemical waste requires a drainage system that provides a safe and long lasting solution in addition to the typical end user requirements of value, efficiency and reliability.

Careful consideration of the individual environment, supported by tried and tested options provide reassurance to the specifier and give end users the confidence that they are choosing a purpose-designed pipe system that will last and won't be compromised over its lifetime.

Chris Ricketts is with BSS Industrial, Leicester, UK.


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