AUTHOR: Murray Cronje, Pr.Tech (Eng.)
SYNOPSIS
The paper will firstly discuss the intricacies of the sophisticated reflector design and electrical construction for electromagnetic interference conformity, for the induction luminaire that was chosen for this project. Then the paper will continue to discuss the principles of the lighting design for the interior of this tunnel, based on CEN and CIE recommendations, including some visual renderings of the tunnel design which were created with the AGI32 software used for the lighting design. And finally the paper will end off with some installation aspects including a day and night-time evaluation of the lighting levels, appearance of the lighting installation as well as some remarks on driver and pedestrian comfort in the tunnel.
Introduction
The Waterval Boven tunnel (previously the NZASM tunnel) lies in the picturesque Elands River valley just outside the historic town of Waterval Boven on the N4 route from Pretoria to Nelspruit and eventually Maputo in Mozambique.
Trans African Concessions (TRAC) are the operators of the N4 toll route between Pretoria and Nelspruit.
As TRAC are in the process of upgrading this route due to the number of toll plazas installed on the N4, they focused their attention on the tunnel on the N4 just outside Waterval Boven.
Details of Old Installation:
The original lighting system in the tunnel consisted of:
1. 40 floodlight luminaires (20 on either side) provided indirect lighting to the carriageway surface. The mounting height of these luminaires was 4,7m. They were mounted in the inverted position directing all the light flux against the roof. The roof has due to its condition a very poor reflective factor (between 10-30%)
2. The 40 luminaires each contained a 400W High Pressure Sodium Lamp. The total load was therefore 17.3kW and electricity consumption was estimated at R3500-00 per month.
3.