Special Project

Direct Communications, a professional installation company based in St Ives, Cambridge-shire, hasbeen involved in an unusual and challenging door entry installation in a luxury Fulham residence comprising of 49 houses.

The project required replacing the existing door entry system, which no longer worked, with a new video and audio door entry system, interconnecting the audio and video from the vehicle and pedestrian gate access areas to each of the homes.

In addition each house was being fitted with an external door entry system at the front door outside each house, and inside on the ground floor a monitor and handset with door release, with additional handsets on the first and second floors.

At the main entrance, the new system had to be fitted into the existing brass push-button panel.

The requirements of the system were to enable residents to communicate with visitors as they arrived. They needed to see and speak to visitors at the vehicle and pedestrian gates and, using the door release, allow the vehicle and pedestrian gates and individual front doors to be opened automatically.

In preparing the tender for SLB Electrical, the main contractor for the project, Direct Communications needed to specify a two camera video entry system capable of working 1- 49 way and also able to operate over the 1500m distance around the houses.

Explained Robin Harper, Project Manager for Direct Communications: "Only two manufacturers were able to provide the right system for us, and we decided to specify the Farfisa FN4000 digital system from BC Access Control. It was the best product for the job, in that it fulfiled all the required functions and came within our tight budget."

David McGinn, Sales Director at BC Access Control recommended the use of the system. He said an analogue system would have been extremely costly and physically impossible using the existing ducting.

"When we realised the distance was 1500 metres we recommended the digital system as it would be more cost effective and easier to install than an analogue system. In this situation the greater the distance between each system, the more cable and power is required."

The system being replaced was thought to have never worked properly, possibly due to the distance between houses

As it was, the cable installation presented quite a few challenges. To start with, the system that was being replaced was thought to have never worked properly, possibly due to the distance between the houses and cabling problems. Direct Communications intended to use the existing ducting for the new installation, however this was not possible as in some places the ducting did not reach the houses as it should have. Unforeseen excavation work was required, which meant a longer programme for the job. Harper continues: "We had to excavate outside to take the old cables out and put new cables in. We found that the main ducting leading to the main entrance had collapsed, so we had to excavate there as well. It was an unforeseen complication."

Due to the long runs of cable, Direct Communications had to increase the diameter from 0.5mm standard cable to 2.5mm to allow for the signal loss over the distance. Since they were installing a digital system they used a multi core12 wire cable, using 9 wires over 1500 metres. 2000m of coax cable was also used.

Harper explained: "The 12 wire cable presented its problems because we actually wanted to loop from house to house, but the ducting was too small. This was not a straightforward process and what we ended up doing was fitting watertight joints in the manholes and spurring out from there to each house.

"There were five circuits, each circuit serving ten houses and the last serving just nine."

It is unusual for a system like this to connect over such a long distance, and in the beginning Direct Communications experienced some teething problems with the audio connection. Farfisa assisted in finding the solution by creating bespoke software to accommodate the long run. Farfisa added two data modules to boost the signal, which worked successfully. This digital system is off the shelf but the application clearly wasn't, as each house had a front panel as well as a connection to the outer gate.

The project was completed in just two months and the new system went live following a one-month test perio, and is running smoothly.

Direct Communications will be maintaining the system for SLB Electrical. Direct had used Farfisa door entry products before but not for such a large or unusual project.