Construction World May 2015

CONSTRUCTION WORLD

MAY

2015

PROJECTS AND CONTRACTS

“Project Lumen had specific

requirements in terms of lightning

protection,” says Trevor Manas,

Pontins’ MD. “Besides the signif-

icant height and size of the structure, it is

situated in an area of very high lightning

density – approximately 12 strikes/km

/year

– and since being switched on in November

2013 it has suffered damage from numerous

direct strikes.”

Pontins is the only specialist LPS

company in South Africa with access to and

expertise in DEHN’s renowned HVI® Conduc-

tors, and was the obvious choice to solve this

intricate problem.

Manas says that the previous ‘Cross

Bonded’ system failed on Project Lumen

because this conventional technology did

not maintain a separation distance between

the lightning protection conductors and

the LED panels or the electrical/data supply

cables of the panels.

Before installing the HVI® Conductor to

SANS/IEC 62305 standards, Pontins under-

took risk assessments and calculated the

required separation distance. The risk

assessments determined that the highest

lightning protection level (LPL) – level one

– was required for Project Lumen. Separa-

tion distance – determined utilising DEHN

Toolbox software – is the minimum distance

between the protection device and electri-

cally conductive materials to prevent flash-

over and sparking, and to ensure that the

lightning currents are reliably conducted to

the earth-termination system.

The ABSA Towers building was constructed

using steel-reinforced concrete. Electric

continuity tests performed on the concrete

steel reinforcing at strategically exposed

points established that the interconnected

reinforcing should be used as natural down

conductors, and natural earth electrodes, to

enhance the division (splitting) of the light-

ning’s current in the event of a direct strike.

“Basically, a conductor must have suffi-

cient current-carrying capacity, be insu-

lated to the sufficient electrical strength

and prevent creeping discharge or flashover

and the particular HVI® Conductor that we

installed fits the bill perfectly,” says Manas.

“The HVI® conductor is unique. This

coaxial conductor has an inner copper core

wrapped in thick-walled high-voltage-re-

sistant insulation that is encased within a

special semi-conductive weather-resistant

sheath,” Manas says.

For this installation, two three-metre

masts were installed, with two HVI® Power

Conductors (LPL 1) carrying the current

down from each mast to the rebar.

“Once we’d established the require-

ments, we designed the isolated air terminal

system to intercept and prevent penetration

of strikes, calculated the height and posi-

tioning of these terminals and the angle

Solving Project Lumen’s

LIGHTNING STRIKE

problems

Leading lightning protection

systems (LPS) provider,

Pontins, has installed a

unique protection system for

ABSA Bank’s Project Lumen

– the world’s largest Light

Emitting Display (LED) – in

the Johannesburg CBD. The

system comprises, inter alia,

an insulated, high-voltage

resistant HVI® conductor,

designed and developed by

Pontins’ German partners,

DEHN, in conjunction with

Pontins’ engineers.

of protection to cover the LED’s steelwork

frames,” Manas says. “We also designed the

earthing, equipotential bonding, current-di-

vision, layout and specialised mast brackets,

which we specifically manufactured, in

order to attach the masts to the I-beams,”

he says. Additional surge-protection devices

completed the LPS.

At that height, dealing with the instal-

lation challenges and safety concerns was

no mean feat. Nonetheless, the installation

was accelerated and accomplished within

three weeks. This was possible because of

the DEHN designed accessories, fittings, and

installation tools used for the task.

Since this showcase project was

completed in December 2014, no damage of

the LED system has been reported.

Pontins is able to monitor the LPS

through ABSA’s CCTV system and Manas

says that Pontins will share footage of Light-

ning striking the HVI® LPS as and when it

becomes available.

Pontins, wholly owned by ELB’s B&W

Instrumentation and Electrical, provides

earthing, LPS and surge protection that

is easily installed, economical, aesthet-

ically appealing, and appropriate to the

widest possible range of industrial and resi-

dential purposes.

Leading lightning protection systems provider, Pontins, has installed a unique protection system for

ABSA Bank’s Project Lumen – the world’s largest LED – in the Johannesburg CBD.