Making a Fresh Start

at Graylingwell Hospital, Chichester

Charles Barrett describes how a particularly difficult job was made easier and more successful using the latest technology

The Client

Knight Frank are a world-wide firm of commercial and residential property professionals. They were commissioned by English Partnerships to prepare the former NHS hospital site at Graylingwell for marketing and subsequent redevelopment.

The Task

Because there were no existing floor plans, measured surveys were required for all the buildings on the site – a combined floor area in excess of 23,000m2.

Graylingwell which is near Chichester is an old mental hospital built in the 1880s with extensions and alterations that have been made at various periods since that time. The site is made up of various ward buildings with long interconnecting corridors covering over ¾ km. There are also a number of other buildings on the site including a farm and a chapel. English Partnerships had taken over the building from the NHS as they had gradually moved services away from the site during the previous few years.

As you can imagine, a site of this complexity with no existing plans was going to be a nightmare to survey in the traditional way. 3i Surveys were chosen by Knight Frank because they had a good track record for quality results in similar circumstances. The production of floor plans for marketing was identified by Knight Frank as being particularly important. A substantial element of the redevelopment will be the conversion of exiting buildings. The floor plans therefore provide an important base for the short listed developers to draw up proposals and  understand the potential of the buildings.

The Equipment

3i Surveys use the latest technology to ensure that drawings of the highest quality and accuracy are produced as cost effectively as possible, even in the most demanding circumstances such as these.

The Survey

The first task was to gain an accurate external ‘footprint’ of each building and an accurate plot of their positions in relationship to each other. This was quickly accomplished using a reflectorless total station. Once these external dimensions were established each building was surveyed internally using the ‘footprint’ as a starting point. The data was output from the total station in AutoCAD ‘DWG’ drawing format and copied onto a handheld PDA device such as the HP iPAQ. The PDA’s use SiteMaster Building – an AutoCAD compatible software package from GraebertUK. It fully supports the AutoCAD layering system and has a multitude of features specifically designed as an aid to surveying. Using this method enabled us to move straight from external surveying using a total station to internal surveying using SiteMaster Building without any intermediate visits to the office to consolidate the external survey.

Inside, the building was a labyrinth. It had corridors leading to other corridors leading back to the entrance, hidden courtyards and rooms leading into previously undiscovered areas. Parts of the ground floor were only accessible by going up to the first floor then back down again via a totally different part of the building. It was enough to get even our best surveyor lost. Our original footprint surveys proved to be invaluable!

Our surveyors’ only other equipment apart from the PDA/SiteMaster Building is a Hilti PD38 Laser Range Meter. This setup is very easy to use and as they could operate individually our team of surveyors worked simultaneously in different parts of a building. One of the main benefits of this new surveying method is that any mistakes were instantly obvious and could be rectified quickly while on site. This is far better than previously when we relied on office based checking procedures often resulting in the need for costly revisits to site.

Another major benefit is that measurements do not have to be typed into the PDA, they come straight from the Hilti using the Bluetooth wireless technology built into both devices. Because of this ‘fingerless’ technology, errors due to poor annotation or the displacement of numbers are completely gone.

The Hilti PD38 has a good clear laser point that can be seen as far away as 30 or 40 meters* so the maze of long corridors posed no problems at all for the survey team. (*Up to 250m if the built-in sight is used.)

With old buildings such as those at Graylingwell, walls are often at very strange angles. This would normally present difficulties for the surveyor involving a lot of work to manually calculate the angles. GraebertUK’s SiteMaster Building, however, does all the calculations for you, again minimising the risk of errors. The software prompts for each measurement to be taken in the correct sequence and then does all the necessary mathematics automatically.

If there is still any doubt at all about accuracy, final checks can be made while still on site. Yet another great feature is that the software automatically records all dimensions taken on a special ‘layer’. Make this layer visible and checks can be made quickly and easily.

As the survey progressed we were able to send our survey drawings back to the office by email directly from the PDAs. At the office they were thoroughly checked and completed by adding drawing borders, orientation signs and any keys to symbology that were required. If any errors were discovered these could be verified with the surveyors before they left site.

Conclusion

After arriving on site and finding a very daunting building that looked almost impossible to survey within the time constraints, we were in fact, quickly able to survey the whole site. It was quickly and easily accomplished with 28000m2 being surveyed in less than 4 weeks.

I am sure you will agree that the results achieved using this approach were impressive.

The Next Step

For further details of the equipment and software used on this survey or details of our surveying services contact 3i Surveys TODAY!