May 10 2005
Decisions made at the design stage are important when it comes to health and safety compliance, environmental performance and obtaining planning permissions. Below are some examples on how BSRIA can help find optimum safe design solutions using diverse computer modelling capabilities for simulating:
- Contaminant dispersion from flues
- Heat dispersion and external windflows
- Solar shading assessment to support planning applications
Contaminant dispersion from flues
Releases of chemicals from flues pose a risk to health and analysis and prediction of this threat should be considered at the design stage. This is especially important for laboratory fume cupboard flues or anywhere toxic fumes may be released.
When fume cupboards are installed in laboratories it is important to consider carefully the design of extract system. According to BS 7258: Part 2 if the building is of irregular shape, or if there are nearby large buildings or topological features then special advice should be sought, since effluent dispersion patterns are likely to be affected.
Using computer modelling BSRIA can analyse proposed layouts of laboratory flues, simulate the external airflow over the structure for selected weather conditions and determine the pattern of contaminant dispersion from the fume cupboard flues. Although discharge from fume cupboard flues can involve regular discharge of a known toxic substance, it is more common for our clients to seek advise on accident scenarios. This presents a challenge to the computer specialist, since data on chemical release rates are an unknown and difficult decisions must be taken on what constitutes a worst case spillage and how the consequences are interpreted.
Knowledge beyond just experience of computer modelling is needed to achieve a successful outcome. A related problem arises with combustion products from plant or industrial discharges. Although toxicity may be far less than fume cupboard accidents, the discharges are long term in nature and an assessment may still be important to address the concerns of locals at the planning stage.
Heat dispersion and external windflows
Positioning of plant in confined and sheltered regions raises a risk of overheating and it is useful exploring design options to find the optimum solution. Backup power supply and HVAC plant need to release heat to the external environment.
However it is sometimes necessary to locate this equipment in confined and sheltered areas, where a risk of overheating is obvious.
BSRIA works on many different applications that are at the design stage and has experience in calculating the patterns of wind flow for selected weather conditions and determining temperatures resulting from the operation of the equipment.
Solar shading assessment - supporting planning application
The overshadowing effect of new structures on existing buildings is commonly raised as a planning issue. It is useful to be able to demonstrate precisely where the shadows will fall and BSRIA have provided this service to architects to assist with planning applications.
Using thermal modelling we can predict the overshadowing effect since this is an important part of calculating solar gains to buildings.
However the software also provides clear graphics showing the location of shadows for each hour of the day and each month of the year. These quality graphics showing the precise location of shadows can provide strong evidence for planning purposes.