Standard solutions

The now complete LINK MCNS research project examined building services solutions for plant room, ceiling voids and risers¹. The solutions developed are based on rule sets collated by the partners. These rules address the selection, sizing and location of equipment. The rules are implemented in Visual Basic software to automate the generation of the solutions. The user specifies what equipment should be included in the solution and sets the performance requirements, eg kW heating load for a boiler plant room. The software selects and sizes manufacturers' equipment from a database to meet the requirements. The equipment is then laid out with appropriate access and maintenance allowances using the location rules.

The resulting solutions can be output to Word and cad (2D or 3D Bentley MicroStation) to reduce drafting time. Other forms of output are also possible including specifications and quantities.

Solutions
Solutions have been developed for a number of plant room types. These include the equipment and connections between the equipment within the plant room. External pipework, ductwork and tray connections are routed manually – it was not practical to standardise this aspect due to the number of possible configurations.

The ceiling void solution is based on a four pipe fan coil system. Whereas with plant rooms the main integration issues are between different services elements, for ceiling voids the emphasis is more on integration with non-services elements such as beams, ceiling tiles and cores. These need to be defined before the services solution can be generated to suit.

The ceiling void services are located approximately in order from the most to least geometrically constrained, starting with luminaires to integrate with the ceiling tiles, diffusers to integrate with the lighting layout, fan coils to ensure maintenance access, and so on. Facilities have been added to deal with increasingly complex layouts, including modification of perimeter diffuser locations to follow a non-linear facade. Distribution routing from the risers to fan coils is manual as it was not practical to standardise this aspect due the number of possible configurations.

Separate mechanical and electrical solutions have been implemented. The user input screens have lists of services that may be selected for inclusion. These act as prompts or check lists and reduce the risk of error by omission. The 2D layouts generated are based on the total capacity of each of the services. To generate floor by floor solutions and a 3D layout, it is necessary to define connections to and from the riser at each level. Sizing of the vertical elements and horizontal take-offs is then determined by the connection requirements.

The implementation work was extended to include full integration of the individual solutions to produce a whole building solution and demonstrate the full potential of the approach. This was achieved by adding interconnecting pipework, ductwork and tray routes between the individual solutions.

The solutions produced were benchmarked against current practice focussing on the space requirements. The solutions were found to be in good agreement with actual design solutions and published sources of space allowance data.

The Visual Basic tools generate solutions for relatively simple geometric layouts. These are directly appropriate for many applications and can also be modified manually to deal with more complex geometries. However, it would ultimately be preferable to directly generate solutions for complex geometries.

The Martin Centre built on the industrial partners work by using constraint modelling to generate solutions for complex boiler room geometries. The Java software tool requires the plant room geometry to be defined by the user in addition to the heating load. Having selected and sized the equipment on the basis of the heating load, a compatible optimising 3D variational solution is generated using constraint logic programming. A number of solutions are generated to suit the constraints and heuristics used to select the most promising. The final step generates pipe routes, using optimisation to minimise the length of pipes and the number of bends.

The resulting software is highly interactive. Modifying the topology of the solution is done directly through the graphic interface by dragging; the system automatically updates the 3D model (including the pipe-routing) while maintaining all the constraints.

Findings
The results from the research demonstrate that it is possible to define and implement standard solutions to produce designs comparable with current practice.

The use of standard solutions in conjunction with IT has the potential to significantly reduce design costs, improve quality and produce additional benefits elsewhere in the supply chain. The main quantifiable benefit is the reduction in design time estimated to be typically in the region of 10-20%. This is based on design activities replaced by the automated generation of the standard solutions.

The team also found that IT implementation of the solutions performs a critical role in maximising productivity improvement by automating generation of the design. Standardisation is widely used in design at present particularly for selection and sizing of plant, but these processes are invariably manual in nature.

Applications most suited to standardisation are characterised by a number of features:

• A high degree of repetition between jobs – otherwise the benefits may not be sufficient to outweigh the development, implementation and update costs.

• A limited number of practical variations – the number of practical variations will impact on the development, implementation and update costs.

• Minimal interaction with other disciplines and services – these require definition of the constraints before a solution can be generated.

Plant rooms and risers are good examples of suitable applications.

Also, partially standardised solutions can be of significant benefit. In some cases it may not be practical to standardise all elements or facets of a solution. Distribution routing in the ceiling void is an example of this. However, much of the solution can still be standardised such as fan coil and diffuser arrangements.

Reducing the scope of a solution may increase suitability for standardisation. For plant rooms it was found to be preferable to limit pipework, ductwork and tray routing to interconnections between plant and connection points within the plant room.

The standard solutions should act as templates that can subsequently be modified to suit an increased range of applications. The standard solutions generated are unlikely to be wholly correct for more than a small percentage of applications. However, with only minimal modification, the bulk of the standard solutions are likely to be appropriate for a much larger range of applications.

A significant barrier to the widespread implementation is the current lack of manufacturers' equipment data in a suitable electronic format. The standard solutions are underpinned by the equipment database from which selections are made. This may be addressed in future by the work of the International Alliance for Interoperability² and others.

Standard solutions should be seen as tools for aiding progress by way of propagating good practice and releasing resources for innovation. Concerns were raised during the project over whether standardisation would present a barrier to progress and innovation. To ensure that standard solutions have a positive effect in this respect, solutions should be continually updated to keep up with and to help propagate good practice. Resources released by the use of standard solutions could be redirected to those areas of design requiring novel solutions to increase innovation.

The plant room and riser Visual Basic tools are now starting to be used in the design process for calculating space allowance requirements. Using the tools saves time and improves the quality and robustness of the information available during early design. It is intended to extend the application of the tools through the design process to outline and detailed design. Research is also planned to extend the work of the Martin Centre for complex geometries and user interaction.

So can standard solutions really deliver productivity and quality benefits to engineers and clients? We think so, but why not use the project outputs to help assess this for yourself by visiting www.standardsolutions.co.uk.