Top considerations for design and build in hazardous environments

Here, Paul Mannion explains the considerations that should be made when designing for builds in hazardous environments

When Mount Vesuvius erupted in AD79, the citizens of Pompeii were not prepared for the devastation that followed.  Now, the Italian authorities continue to prepare for the next eruption from one of the most dangerous active volcanos in the world.

The Dangerous Substances and Explosive Atmosphere Regulations 2002 (DSEAR), defines a hazardous area as “any place in which an explosive atmosphere may occur in quantities such as to require special precautions to protect the safety of workers”.

It’s vital that precautions are taken when constructing, installing and using apparatus in areas that are defined as hazardous.

Identifying hazardous environments

Hazardous areas are classified under six zones. Three zones associated with gas are classified under Zone 0 and are areas where an explosive gas atmosphere is present. Zone 1 is an area where an explosive gas atmosphere is likely to occur in normal operation. 

While Zone 2 covers areas where an explosive gas atmosphere is not likely to occur in normal operation. 

The other three zones are associated with dusts, which are either flying and explosive, conductive or non-conductive.

Any facility that processes, uses or manufacture’s materials that may give rise to a flammable atmosphere, such as gas, mist, liquid and small fibres (dusts), may have a potentially explosive atmosphere. 

Industries that may have an explosive atmosphere, include food manufacturing, power generation and chemical manufacturing and pharmaceutical.

Boulting’s qualified electrical engineers always visit a site before beginning work to ensure the relevant protection systems are in place. 

By visiting the site beforehand and conducting the appropriate risk assessments, Boulting’s engineers can ensure that the build is specifically designed for that unique environment, taking into consideration any potential risks.

While areas classified as Zone 0 or Zone 20 continuously face the potential for the creation of an explosive gas or dust atmosphere, work still needs to be conducted in these areas. 

The equipment used needs to be weighted so that there is no chance of creating explosions. 

Equipment should be designed in such a way that it is stringently safe and includes current limiting devices to stop sparks.

Before equipment can be used in any hazardous area, it must undergo rigorous checks and testing by a registered ATEX test house. ATEX is the name given to two European directives that aid in controlling explosive atmospheres. 

The first, Directive 99/92/EC (ATEX 137) assess the minimum requirements for improving health and safety protection for workers in potentially explosive environments. Directive 94/9/EC (ATEX 95) looks at the laws concerning equipment and protective systems intended for use in potentially explosive environments.

Constructability

When constructing a new facility or working in an existing environment, it’s important that the installation of new components is done using the most efficient techniques to reduce the risk of incidents.

Modularisation is a technique often used by Boulting. This method sees equipment or parts of a facility built offsite and installed later, taking the risk out of working on a hazardous site. 

Modular builds reduce site disturbance, minimise waste, are more cost effective and allow for greater design flexibility.

Maintainability

While ATEX testing is vital to identify and resolve potential risks at the start of a project, it’s important that inspections continue on a regular basis throughout the equipment’s lifespan.

At Boulting, we provide clients with a digital cloud based system where they can upload inspection schedules and what exactly needs to be checked. 

Many plant managers are now integrating hand held devices, that allow engineers to upload information directly into their database, making the process easier to manage and permitting the production of incredibly concise reports.

Just as the Gulf of Naples continues to prepare for the hazards associated with living in the shadow of an active volcano, it’s vital that engineers meticulously plan and test when looking to design and build in their own hazardous environments.

Paul Mannion is project engineer at engineering solutions provider Boulting.