To prevent an excessive build-up of carbon monoxide (CO) from diesel engines in enclosed spaces, sufficient ventilation must be provided. This will ensure that the stipulations of the Approved Document F (ADF) are met and that good air quality is sustained.
Carbon Monoxide is a silent killer. It is colourless, odourless and tasteless, and is formed from incomplete combustion. This occurs within internal combustion engines and is present in varying degrees in all vehicle exhaust systems. Therefore, it is vital to control diesel engine exhaust emissions in enclosed spaces such as warehouses and distribution hubs.
The Health and Safety Executive (HSE) explains the health risks of exposure to exhaust fumes in the workplace in INDG286 and provides detailed guidance on how to control exposure to exhaust emissions in the workplace in HSG187. However, as vehicle movements and so exhaust emissions in warehouses fluctuates during the day with several vehicles entering and exiting the building at similar times, applying such prescriptive guidance can be difficult.
In this post, we explore why there are no one-size-fits-all solutions when it comes to controlling diesel exhaust emissions in enclosed spaces such as warehouses.
When Local Exhaust Ventilation (LEV) is a viable solution
Controlling diesel engine exhaust emissions in enclosed spaces can be easily achieved with LEV where vehicles park in predefined locations for a reasonable period of time. LEV carries away airborne contaminants before they can be inhaled. An LEV solution can be implemented by fitting pipes to the vehicles’ exhausts while they are being serviced and are mainly stationary to draw the fumes outside.
When LEV is not possible
As we mentioned above, there is no one-size-fits-all solution to controlling diesel exhaust emissions. LEV would not be a suitable solution in instances where there is frequent movement inside a warehouse from vans and lorries entering and exiting the building to be loaded and unloaded.
Designing out-of-the-box solutions
As prescriptive guidance can be difficult or expensive to apply, more flexible solutions need to be identified, designed and implemented on a case by case basis. Colt offers expertise and can design bespoke solutions that are effective, and significantly cheaper than the standard, prescriptive solutions. We frequently work with consultant engineers and architects to design ventilation systems to control exhaust emissions from the delivery vans.
What needs to be considered during the process of designing an effective ventilation system when LEV is not an option?
- The layout of the building must be analysed and its use; vehicle movements and the size and type of the vehicles’ engines must be assessed and taken into consideration.
- The temperature of the facility is important and must also be taken into account. As these types of facilities tend to be unheated, this is an important consideration because exhaust fumes are relatively hot so will tend to rise. In an unheated space, it will cool as it rises and therefore may not reach the roof extracts forming a ‘fume cloud’ within the building, requiring low and high-level extract grilles.
- Monitoring the air quality and linking CO detection to a variable duty ventilation system can add a further level of efficiency.
An example of how we designed a feasible solution to control diesel engine exhaust emissions in a warehouse
The work that we carried out at The Royal Mail’s Parcelforce sorting and distribution centres required us to find an effective and cost-efficient solution. We had to think outside of the box
to achieve this.
Parcelforce’s centres are often converted warehouses and can contain up to 150 vans at any one time, all entering and exiting the building at similar times. Whilst the standard ADF would prescribe 6 air changes per hour, we recognised that there would be peaks at the times vans drive in or out. Therefore, exhaust emission levels would go down when vehicles were stationary while loading or unloading the parcels, or when the building was empty between rounds of deliveries and collections.
Colt’s early involvement with Parcelforce enabled us to support the M&E consultant from initial design through to approval with building control.
The Royal Mail was able to tell us when and how the van movements occurred with specifics in terms of roadways and bay layouts, which enabled us to tailor the design.
Taking into account the considerations listed above, we developed a system which achieved cross-flow ventilation via natural inlet air and mechanical extract with a combination of axial fans and natural ventilators. These are triggered by CO detectors when the emission levels reach a pre-determined level.
This means that mechanical extraction fans will only operate when needed, significantly cutting operating costs.
This approach applies equally to other companies providing a parcel delivery service or operating a goods distribution hub.
Thanks for taking the time to read this post. If you are in a situation where LEV is not a feasible solution and need help to design a bespoke solution, it is a good idea to involve experts from the very early stages of your project. Do not hesitate to contact us for more information.
If your building is too hot or too cold, if your process gives off fume or moisture, if your product requires specific conditions during its manufacture or storage, or if noise is a concern, then we may be able to help you.
We can survey your building using a range of techniques and equipment to identify your problem. Once established, we can then recommend a solution based on proven design work.
Paul Langford is an Engineering Director with experience in product development, manufacturing and testing for HVAC, solar shading, louvre systems and smoke control applications.