SLC and PCM install at Liberty Hall Theatre, Dublin

When it came to custom engineering and installing the specialist lighting bars required at the front-of-house and forestage positions, Stage Lighting Centre’s Paddy Farrell approached PCM.

Working to the very strict aesthetic directive of Dublin-based Architects, Brian Hogan & Associates, the FOH lighting bars had to be secreted as high up in the auditorium roof as possible.

To maximise this very tight roof void space, PCM designed and installed two 9-line lighting bar winches, each of which raises and lowers three independent 6-way lighting bars. When in the ‘up’ position, the bars are tucked tight up to the ceiling in the theatre’s open-plan roof – completely unobtrusive for sight lines, yet able to hit the necessary onstage positions with ease.

Each lighting bar winch was supplied by PCM, complete with two 500 Kg GIS motor units, a clewed travel-and-track system, head and divert pulleys, steel cable, cable terminations, suspension bars and power reels.

Power and Data reels

For extreme neatness, power and data cables feed direct to the lighting bars via six spring-loaded power reels (three for data and three for power). These allow for power and control cables running to the lighting fixtures to be contained on a drum. This greatly improves the cosmetic appearance of open auditoriums like this – no more huge unsightly cable loops and tape!
The Power Reels also alleviate the need for hauling multicore cables up to the lighting bars when there is a lantern reconfiguration, as all necessary cables are already in place to accommodate any changes. Maintenance also becomes easier with the reeled cables, as the bars can easily be lowered in to floor level, worked on, and raised again without having to haul cables on and off.

Challenges

The trickiest part element of the job for PCM was fitting the bars and winch system amongst the web of concrete structural supports of the auditorium roof. Brian Hogan & Associates stipulated that nothing could be drilled or rigged directly onto to the theatre’s roof beams.

The solution was to lock each of the lighting bar winch tracks solidly into position via 10 special seating plates, located into the central nodes where the concrete roof supports meet. Each seating plate was designed to allow the clew plate and pulley track systems of each lighting bar winch to be securely fastened, making the whole arrangement into a completely solid and immovable structure.

PCM also supplied and installed a complete proscenium curtain track system and a roof mounted motorised projection screen. Stage Lighting Centre additionally installed new Strand LD90 dimmer racks, stage curtains, a Strand Series 300 lighting console and new lanterns, primarily Strand SL and Cantata fixtures.

Brian Tracey, Liberty Hall’s Head of Technical comments “The installation of the lighting bars greatly improves our ability to quickly and safety de-rig and re-rig each of the front of house lighting bars. Stage Lighting Centre and PCM worked incredibly intuitively on this very challenging contract”.