Chimney Dismantling

Churchill have successfully completed the piecemeal small dismantling of a 50m tall x 2.2m diameter disused steel chimney on a COMAH 1 site in Stowmarket.

To add to the complexity of the project that would see a requirement for hot work at height the chimney was situated adjacent to a live railway line managed by Network Rail that determined cranes could not be used as part of the project.

The chimney was dismantled within budget and completed within an eight week program

BS 7671 - Surge Protection Section (534)

Surge Protection - Latest BS 7671 Wiring Regulations

A new key section (534) within the latest edition of BS 7671 Wiring Regulations published on the 1 July 2011 came into  effect on 1 January 2012.

Section (534) now sees a requirement for all new electrical installations designed after 1 January 2012 to include the correct selection and installation of a SPD's (Surge Protection Device).

This requirement is to provide protection against over voltages from atmospheric origin (lightning) or electrical switching events both of which are capable of severely effecting electrical installations and connected equipment.

The risks to life, buildings and electronics due to over voltages are detailed within BS EN 62305 'Protection Against Lightning' with the standard clearly detailing a risk assessment to establish the type and level of SPD's required.

Churchill offer a full range of SPD's manufactured by the world's leading suppliers, this is supported by free comprehensive advice together with free seminars to larger clients explaining the fundamentals of SPD's.

The most popular SPD on the market and the one most commonly installed is the Furse ESP 415 M1 which is an enhanced protector for three phase supplies of 346 - 484 volts, for single phase supplies of 200 - 280 volts the ESP 240 M1 should be employed.

For more information of SPD's call our helpdesk on 0844 504 9998

The Origins of Lightning Protection

Lightning protection science was first conceived by Benjamin Franklin in 1749 with his invention of the first pointed lightning rod conductor that became known as a “lightning attractor” and much later  as the “Franklin Rod.” Franklin spent many years in the lightning protection design process to include his famous kite experiment, which took place as he was waiting for permission to test his theories on the new Christ Church structure in Philadelphia, PA. Although Franklin did not patent any of his inventions, he published advice on lightning protection in Poor Richard's Almanac in 1753.

At that time, common belief was that lightning was a creation of God and therefore should not be interfered with in anyway. Franklin was finally able to convince the church deacons that they should take precautions against lightning damage by installing the lightning protection he designed, citing that rain was also a creation of God but roofs were still used on buildings to protect people and contents of buildings.

During the 19th century, lightning protection became an architectural addition to many public and private structures. The overall pointed rod design was complimented with ornamental solid glass balls, which were not only decorative but were believed to be an integral element in the effectiveness of the lightning protection of the structure. The theory behind this addition was that since glass is a non-conductor of electricity that they would repel the charge and for a time, because of the erratic behaviour of lightning it was believed this was scientifically proven.

Both the pointed design and the addition of the solid glass balls were soon proven by Nicola Tesla to be a flawed lightning protection design. Tesla's patented design was a great improvement over Franklin's original lightning protection of the pointed rod. In 1919, years after receiving his patent, Tesla publish an article, “Famous Scientific Illusions” in The Electrical Experimenter explaining the logic he used to dispel the science of Franklin's pointed lightning rod and scientific knowledge he used to design his lightning protection device. In his article, Tesla proved that the pointed tip of the iron rod actually ionised the air around it, which rendered it air conductive and raised the probability of a lightning strike.

Over the decades, since Franklin and Tesla, there has been much progress in lightning protection systems. Great innovations in design and methodology have advanced the protection of mission critical systems for military and government operations and commercial applications. From transportation system control centres to mobile phone transmission towers, the instances of catastrophic damage to these and other services we had all come to take for granted has been greatly reduced.

10 Interesting Facts about Lightning

With lightning being a specialty here, we have decided to share with you 10 interesting facts about lightning!

1. A single bolt of lightning is around 50,000f or 5 times hotter than the surface of the sun.
2. The irrational fear of lightning is known as keraunophobia.
3. There are two types of lightning, negative strikes and positive strikes. Positive strikes are 5 times more powerful than negative strikes.
4. The odds of being struck by lightning in your lifetime is 1 in 3,000.
5. Most lightning strikes average at 2-3 miles long and carry a current of 10000 Amps at 100million volts.
6. Each second there are 50 to 100 Cloud-to-ground lightning strikes to the earth worldwide.
7. The Empire State Building in New York is struck 24 times a year and was once struck eight times in 24 minutes.
8. An average instance of lightning lasts about a quarter of a second and consists of 3-4 strikes
9. The energy contained from a single lightning strike can power a 100 watt light bulb for 90 days.
10. "Lightning never strikes twice" is just a myth, lightning can strike the same location many times.

How Lightning Damages Buildings

Lightning is both amazing to watch, and also highly destructive. The amount of energy a lightning strikes imparts on an object means damage to people and buildings can be significant. It isn't just the strike itself though that causes the problems, there are in fact three ways in which a lightning strike on a building can be devastating.


Physical
Unsurprisingly, most lightning damage is on the rood of a building although this isn't always the case. Roofing titles, chimneys and other roof furniture like satellite dishes and air conditioning unites are often most at risk. However it isn't just this immediate physical damage that is the biggest problem, the risk of fire that can follow a strike is recognised as the biggest potential threat to any building. Tall buildings are especially vulnerable therefore it is rare to see prominent buildings without some form of lightning protection.

Conduction
Of course, anything metal both attracts the strike and then conducts the electricity, this can often be carried deep inside a building causing irreparable damage to electronic equipment. It's not just electronics that spread the damage around though; plumbing is just as likely to create problems. In fact, the conductive nature of metal can be so attractive to lightning that even hidden pipe work underground can often be in the direct firing line.




Electromagnetic
Finally, it doesn't even have to be a direct strike to cause problems, electromagnetic fields caused by a strike can create havoc with computer equipment and other sensitive electronics. Many choose to protect themselves by fitting surge protection devices in addition to physical protection. Whilst physical damage can often be repaired, the loss of data which is possible with the Electromagnetic fields has the potential to be extremely costly and disruptive to businesses heavily reliant on data communications.

The Basics of Lightning

We've talked a lot about lightning protection but not actually about the phenomenon of lightning itself to understand how protection works its worth having a look at why and how lightning strikes.

The lightning most frequently referred to in terms of lightning protection is cloud to ground lightning, other forms of lightning exist but cause less damage to buildings and people than this particular recognised form of lightning.

A lightning strike originates about 15,000 to 20,000 feet above sea level and works its way down to about 50 yards above ground, it’s about at this height that will determine the attachment point which is the point where lightning will strike. The currents in lightning range up to 400kA with average individual stroke of lightning ranging between 25kA to 40kA, the total current will be divided between the different paths of the lightning strikes.

When lightning strikes a stepped leader works its way towards the ground and is met by an upward leader that comes from the ground then a number of return strokes occur which are flashes from the point of contact to the cloud.

Lightning strikes cannot be prevented, they can only be intercepted or diverted onto a path that if well designed will not result in damage, injury or loss of life. Any designed path to earth should have a low impedance connection to earth; this means that the opposition to the flowing current should not be high. The measure is calculated using a complex formula but a protection system can be designed to have low impedance connection.

Lightning protection should always be installed by certificated ATLAS accredited lightning protection designer, if this is not possible measures should be taken to ensure that the installation is assessed by a suitably qualified ATLAS company and that the lightning protection installation will work and protect the building and its occupants against the effects of a lightning strike.

To discuss your lightning protection requirements email our design team at info@churchillsc.co.uk

Selecting Conductors For Your Lightning Protection System

One of the most important components of any lightning protection system is the actual lightning conductor. Conductors are available in two different materials, aluminium and copper and a range of different widths, the most common width used in the UK is 25x3mm.

Designers of lightning protection system will establish the correct width and length from the formulas needed to design the system to ensure the down conductors are capable of transferring the energy and forces of a lightning protection strike safely to earth.

To assist architects and designers of buildings conductors are also available in a wide selection of PVCs lightning protection is required for modern buildings there are a range of pvc covered colours for both aluminium and copper conductor tape. These colours such as black, green, grey, stone, white and brown have been selected to blend in with most modern buildings so the aesthetic impact of the conductor is reduced.

Conductors are also available in flat, solid circular and stranded versions. Flat tape lightning conductors are the most traditional and is also considered to be the easiest to install and where a degree of flexibility is required in a conductor there is also the option of fitting a copper braid.

Solid circular conductors are usually used in conditions where the aesthetic considerations are important, the solid circular conductors are still fairly easy to install but unlike the flat tape systems a straightening tool is required to achieve the desired finish, although it is rarely used in large applications there is also the option of using a stranded cable conductors.
If you require any assistance with the design of your lightning protection system or would like a sample of the products available please visit our ecommerce web site to request samples and assistance.

At Churchill’s we offer the complete solution from design to install however if you simply wish to purchase your lightning protection equipment and have it delivered anywhere in the UK within 3 working days this unique service is available via our on line store.