Let there be light for Manchester Unity's brighter future

Media item: article

Date published: 17 September 2012

This page records the media item. The original article is the property of its publisher and is not reproduced here.

The archive preserves the headline and the date. What follows is general information on heritage facade lighting — a genuinely technical subject, and the one this item points at.

Note: a second archive entry exists for this item under a near-identical headline at Let there be light. It points here. The later coverage of the same scheme is Manchester Unity all lit up again.

Why heritage facades are lit at all

It looks like decoration. It is mostly three other things:

Legibility. A building like the Manchester Unity Building is designed to be read vertically — continuous piers, recessed windows, a stepped tower. In daylight the modelling does that work; after dark the facade flattens into a silhouette. Lighting restores the depth the architect designed in. The design itself is described in Have a Deco at a Classic and Manchester Unity Building.

Civic presence. Lit buildings define a city's night-time character, and heritage buildings are usually the ones people navigate by. A dark facade in a lit street reads as vacant, whatever is happening inside. On the building's place in the city, see Our City: Manchester Unity Building and Melbourne, Australia: Manchester Unity Building.

Safety and activity. Well-lit street frontages support pedestrian activity after dark, which is a public-realm consideration rather than an aesthetic one — and, for anyone walking to an appointment, see Our Location.

Why faience is difficult to light

This is the technical heart of it, and it is specific to this building's material.

The cladding is faience — glazed architectural terracotta, cream in colour, with a hard reflective glaze.

Four problems follow:

1. The glaze is specular. A glossy surface reflects light rather than diffusing it. Aim a bright source at it and you get hot spots and glare rather than an evenly lit wall — the opposite of what the modelling needs.

2. Cream is unforgiving of colour temperature. A light source that is slightly too warm turns the facade orange; slightly too cool turns it grey and lifeless. Getting the colour of the light right is harder than getting the quantity right, and cream shows every error.

3. The depth is the point. Lighting a facade flat from the front destroys exactly the vertical modelling the design depends on. Grazing light from close to the surface reveals the piers and recesses — but grazing light also exposes every crack, every crazed glaze and every mismatched replacement block. The repair work behind that is described in Inside the Manchester Unity Building.

4. Nowhere to put the fittings. Which brings us to the constraint that governs everything.

The constraint: it is on the Victorian Heritage Register

Works to a registered place require a heritage permit unless an exemption applies, and lighting is works.

What that means in practice:

• Fixings are the whole argument. Every bracket is a hole drilled into historic fabric. Conservation practice minimises the number, locates them in mortar joints or replaceable elements rather than through original blocks, and specifies non-corroding materials — because a rusting fixing in a terracotta block splits the block.
• Reversibility. New work should be removable later without loss to the original fabric. A lighting scheme is expected to be a layer added to the building, not a change to it.
• Visibility of the equipment. Fittings, cabling and conduit should not be visible by day. Concealing them without cutting into the fabric is most of the design work.
• Appearance is managed, not only fabric. For this building Heritage Victoria maintains an agreed signage policy, under which signage complying with the criteria is permit exempt and anything outside them is not.

Obtrusive light

The other regulatory dimension, and the one most people never consider.

‘Obtrusive light' is light that goes where it is not wanted, and it is a recognised planning and standards concern. The categories:

• Light spill into neighbouring windows — a serious matter in a city block with residential upper floors
• Glare to pedestrians and, critically, to drivers and tram operators
• Sky glow — upward light, which is wasted energy and a direct contributor to urban light pollution
• Curfews. Many schemes are required to dim or switch off after a set hour.

Australia has standards addressing the control of obtrusive light, and a facade scheme in a city centre is designed against them. Aiming light upward at a building and letting the overspill continue into the sky is the exact thing they exist to prevent.

What LED changed

The shift from discharge and halogen sources to LED altered facade lighting more than any other development, and the reasons are practical rather than aesthetic:

• Optical control. LEDs are small directional sources, so light can be put precisely where it is wanted and nowhere else — which addresses spill, glare and sky glow at the same time.
• Miniaturisation. Small fittings can be concealed in reveals and behind cornices, which reduces the number and visibility of fixings — the heritage constraint.
• Energy and maintenance. Substantially lower consumption, and far longer service life. On a facade where every relamping means access equipment on a public street, lamp life is a major cost.
• Colour control. Adjustable colour temperature, and the ability to tune the light to the actual colour of the stone or glaze rather than accepting what a lamp produces.
• Dimming and scheduling, which makes curfews and seasonal variation straightforward.
• No ultraviolet or infrared in the beam, which matters for conservation — heat and UV degrade historic materials and finishes.

The trade-off worth naming: LED made facade lighting cheap and controllable enough that the temptation is to over-light, and to add colour-changing effects. Conservation practice is generally against both. The aim is to reveal the building, not to decorate it.

The other Manchester Unity Building pages in this archive

• Have a Deco at a Classic — origins, Marcus Barlow, the Chicago Tribune Tower influence, and faience
• Inside the Manchester Unity Building — the arcade, the escalator, the restoration, and how to reach the practice
• Party time to mark milestone — the Oddfellows, and how Australians paid for health care before Medicare
• Art Deco oasis in the heart of Melbourne
• Barry Humphries gets his teeth into art deco beauty
• The Manchester Unity Building — Costa Rolfe
• Manchester Unity Building — John Gollings
• Manchester Unity Building — Penny Craswell
• Manchester Unity Building — Leonard Joel
• The new shopping centre opens today
• Open House: Melbourne Open House, Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7

Two further items borrow the building's name without being about the building: Mothers in Unity, which is about maternal oral health, and Unity in Smiling: Suzanne Carbone, which is about oral health and mental health.

The complete archive index is Our Media.

Common questions

So does bolting a light onto a heritage-listed building need a permit or not?

It depends on what is being bolted on, and the answer is published. Heritage Victoria applies general exemptions to every place on the Victorian Heritage Register, which exist "to allow everyday activities, maintenance and changes to your property, which don't harm its cultural heritage significance, to proceed without the need to obtain approvals under the Heritage Act 2017." On top of those, each place has its own specific exemptions.

For this building the specific exemptions covering the exterior are short: "minor repairs and maintenance which replace like with like" and "removal of any extraneous items such as air conditioners, pipe work, ducting, wiring, antennae, aerials etc, and making good." Note the direction of travel — taking accumulated equipment off the facade is exempt; the list does not extend to putting new equipment on. Two further conditions apply to everything exempted: work must be "planned and carried out in a manner which prevents damage to the fabric of the registered place", and nothing in the exemptions relieves an owner of the need to "seek relevant planning or building permits from the responsible authority."

How do I look this up myself?

Free, in about a minute. The building is on the Victorian Heritage Register as VHR number H0411, and it also carries Heritage Overlay HO590 in the local planning scheme. Its record on Heritage Victoria's Victorian Heritage Database is place 728, listed under its full registered address — 220-226 Collins Street and 91-107 Swanston Street — and it holds the statement of significance, the history, a plan, images, the permit exemptions and the exemption policy, with the whole record downloadable as a report. Anything a page tells you about this building's protection can be checked there against the State's own words.

Why is it that colour, and why does that make it hard to light?

Because the material was chosen for mass production, not for floodlighting. Heritage Victoria describes the exterior as clad in "biscuit coloured terra cotta faience", "intricately moulded to produce continuous narrow columns and shafts rising up the facade, serving to emphasise the verticality of the building."

The reason it exists at all is industrial. Citing Apperly, Irving and Reynolds, the register's history notes that Australian buildings took up architectural terracotta faience after the 1913 Woolworth Building in New York, that it was "especially popular during the 1930s when it enabled designers to chose from a wide range of colours", and that "the versatile material enabled complex Gothic shapes to be mass-produced from moulds." So the facade is a repeated moulded relief in a pale glazed ceramic — which is precisely the combination that produces hot spots under a bright source and loses all its modelling under flat light.

Practical details

Smile Solutions, Level 1, 220 Collins Street, Manchester Unity Building, Melbourne VIC 3000. Phone 13 13 96, or theteam@smilesolutions.com.au. Monday–Friday 8.00am–6.00pm, Saturday 8.30am–1.30pm, Sunday by appointment. See also Contact Us and Our Team.

Every practitioner's registration can be verified free on the AHPRA public register at ahpra.gov.au.

This page records a published article and its date. The technical and heritage material above is general background rather than a summary of the item; for authoritative heritage information consult Heritage Victoria and the Victorian Heritage Database, and for lighting requirements the applicable Australian Standards and local planning controls. The building is not a claim about clinical care. This is not a diagnosis or a treatment plan. Third-party published content is not reproduced.

Smile Solutions trades under ABN 28 193 514 103.