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.

Surge Protection

When designing lightning protection it's important to consider adequate surge protection. On a smaller scale people protect their treasured home electrical devices with surge protection devices, on a larger scale devices are available to protect a wide range of items such as servers, communications, data storage, telephony etc.

There are a number of forms of protection needed against surges as there is more than one type of surge. One type of surge is transient over voltages which are short duration high magnitude voltage peaks with fast rising edges, often described as "spikes". The most common cause of these spikes is lightning strikes, but they can be caused by electrical switching when there is increased demand placed upon an electrical system it becomes overpowered. These surges can cause devastating damage to systems that are not protected. The most severe damage is to cable installation which in a worst case scenario can result in fatalities through either electric shocks or fire. Other damages can be to electrical and electronic equipment resulting in data loss, degradation and equipment failure. These aspects can cost a company a lot of revenue, in terms of a loss of productivity, product spoilage, staff overtime and delays to clients, not forgetting sales lost to competitors when your business is unable to run smoothly.

There are different types of surge protection devices dependent on the type of transient over-voltage. Direct lightning strikes are protected by lightning current or equipotential bonding SPDs. Indirect lightning strikes and switching transients are protected by transient over-voltage SPDs. The main purpose of lightning current and equipotential  bonding SPD's are to prevent sparking from cable damage by lightning strike, so the site does not become a fire hazard. Transient over-voltage SPD's are there to protect against secondary effects of indirect lightning and switching transients such as data loss and equipment failure.

There are certain areas that require surge protection in order for the protection to be adequate. You need to protect all cables which enter and leave a building including mains power supplies (including UPS), data communication and local are network cables, signal, control, instrumentation and alarm lines, CCTV, satellite, TV and antenna cables and telephone and telemetry lines. It is also important to protect the power supply local to important equipment, electronic equipment outside the main building.

Whatever the surge protection needed you can get both surge protection devices and advice from Churchill Specialist Contracting.

Lightning Protection - Metal Theft

The theft of metal is continuously on the increase and whilst ever scrap prices remain high unfortunately it is a trend that will continue to blight so many including schools, hospitals, hotels, railways in fact any building or structure fitted with lightning protection.

Lightning protection systems commonly consist of copper or aluminium and why PVC sheathing can be fitted to take away the initial obvious presence of either copper or aluminum thieves very quickly get to know and become more aware of where and how lightning protection systems are installed.

Lightning protection systems are installed to almost every new commercial building constructed in the UK however where new modern constructions allow the use of structural steels to be incorporated reducing the opportunity for theft, existing structures do not always have this luxury. As a result external copper and aluminium down conductors are installed and unless they are adequately protected become a very soft target for thieves and vandals.

As a conductor we have recently witnessed a huge increase in the amount of enquiries from local councils, hospitals and businesses requiring stolen down conductors replacing, often security at schools and hospitals is in adequate so any additional precautionary measures need to be considered.

To prevent the theft of copper and aluminium down conductors Churchills supply and fit vandal/theft guards that are simply fitted over the down conductor secured with anti vandal fixing thus fully protecting the downtape conductor and preventing theft/damage.

The vandal/theft guards are economical and quick to install and offer a complete deterrent against theft or vandalism.

For more information on the supply and installation of this very simple but highly effective product please contact us on 0844 504 9998 or visit our web site where guards can be purchased for self installation.

Earthing Equipment

An essential requirement of all modern day structures and systems is an efficient and effective earthing system with a suitable earthing system being a key part of any lightning protection installation.

All earthing systems require specific key components in order for them to be beneficial, with lightning protection the designer planning the earthing system must decide on the conductor type to be used of which there are three commonly used types of conductor:

- Flat tape

- Solid Circular

- Stranded Cable

Above ground there is a choice of conductor materials that can be used, albeit the choice is often between copper or aluminum, however below ground the most appropriate conductor material is copper, this is mainly because copper possesses greater anti corrosion properties.

Earth rods and earth plates are commonly used as Earth installations, the primary function of earth rods is to take advantage of lower resistivity soils at greater depths than standard excavation will allow. Earth plates are used to attain an effective earth in shallow soil where ground conditions are not conductive for installing earth rods.

All effective earthing systems also rely on connections and joints that provide good electrical conductivity with high mechanical strength. Joints and connections that are poorly chosen and incorrectly installed will potentially damage and compromise the performance of the earthing system.

A high quality electrical connection is required, exothermic welding is a straight forward method that uses no external power or heat source. Connections are created using the high temperature reaction between powdered copper oxide and aluminium. Correct connections will never loosen and are highly conductive and have exceptional corrosion resistance.

Compression connections may be used in circumstances where exothermic welding is not suitable for creating long-lasting connections. Very sturdy joints can be provided by compression connectors, they can be buried in the ground or in concrete.

When permanent connections are not appropriate, the ideal method is mechanical clamps. Mechanical clamps are more often used on smaller scale installations where periodic disconnection for testing is required. Top quality mechanical clamps are manufactured from high copper content alloy and will as a minimum posses mechanical strength, outstanding corrosion resistance and conductivity.

It's crucial that all earthing systems receive frequent inspection and testing, installation inspection pits enable easy access to earth electrodes and conductors. A reliable and convenient way of providing a common earth point is via the use of earth bars, integral disconnection links mean the earth bars can be isolated for testing purposes.

In areas where necessary resistance levels are difficult to obtain, Earth electrode backfills can be used, these products such as Marconite or Bentonite effectively enhance the electrodes surface area thus reducing its resistance to earth.

Whether you have a contractual requirement to gain certification to OHSAS 18001, or one of the growing numbers of organisations looking to reduce the overall risks to the organisation and demonstrate good governance, there are a number of key benefits with implementing a certified OHS management system. These include:

• a structured approach to hazard identification and risk management which can contribute to the provision of a healthier and safer working environment and the avoidance of a high proportion of accidents and occupational health problems – this should help reduce lost time through employee illness and injury
• the management of health and safety becoming more transparent and effective by translating the outputs of risk assessment, audits, inspections, legal reviews and incident investigations into action plans to minimise the risk of accidents
• improved staff morale, potential reductions in liability claims and lower insurance premiums
• increased credibility from having an OHS management system independently assessed

In the world of contracting employing an organisation accredited to OHSAS 18001 provide unrivalled confidence that a business not only has safe systems of work in place it also takes very seriously it’s role and responsibilities in protecting the well being of it’s own employees together with those who have a potential to be affected by it’s undertakings.

In a world demanding a requirement for accreditations and compliance it is very easy for the value of OHSAS 18001 to be lost amongst a plethora of more easily available and less stringent and demanding alternatives, OHSAS 18001 has always been and will remain the pinnacle for all organisations serious about their health & safety & occupational health obligations.

As more organisations wake up to the value of OHSAS 18001 more emphasis will be placed on a requirement by blue chips to seek to employ accredited companies, as this spreads only then can the construction world benefit from reducing injury and fatalities which blights the sector.

Why compromise, employ an OHSAS 18001 accredited contractor and discover the future of contracting......

Chimney Inspections

The inspection of single flue industrial chimneys is regulated by the HSE document GS53 and the ATLAS guidance booklet that builds upon the HSE document GS53.

The self supporting single flue steel chimney has commonly been used for a period in excess of 35 years during which time many have seen a change over from serving coal to oil through to the modern day gas fired boilers. This change over in fuels has left its own legacy creating very corrosive environments, this coupled with the effects of the UK climate has led to a large number of this type of structures ultimately failing, hence the HSE Guidance Note GS 53 was published in 2001.

For multi flue industrial steel chimneys the inspection guidance issued for single flue steel chimneys does not apply, the inspection of a steel multi flue chimney i.e where the waste gases do not come into direct contact with the main supporting structure, is covered in Appendix A of BS 4076 :1989.

At present there is currently no inspection guidance for concrete or brick chimneys, however due to the harsh environments and processes related to their use it is prudent to regularly inspect concrete and brick chimneys to ensure they remain in a serviceable condition.

A chimney inspector must be able to prove competency and experience with a minimum preference of being industry qualified via the NVQ route.

Work at Height Hierarchy of Risk

Via risk assessment the use of a mewp to facilitate access to structures should always be the access method of choice particuarly for the completion of surveys.

In the uk truck mounted MEWPS can provide access up to working heights upwards of 70 metres.

During a recent meeting between the hse and the steeplejack federation ATLAS the hse voiced their concerns into the mindset of the steeplejack industry in relation to risk assessments for working at height and our industries continued insistance to survey structures using traditional ladders as apose to MEWPS.

Wherever it is practicable to do so Churchills always look to employ MEWPS for completing surveys of structures up to 70 metres, unfortunetly industry as a whole needs educating in relation to the Work at Height Regs it is only then that the additional cost for the use of MEWPS will become broadly accepted.

Concrete Chimney Demolition

The removal of 3no 60m steel flues from within the reinforced concrete windshield at the old Roche site in Welwyn Garden City was safely completed with the use of a 300 ton mobile crane.

The 3no flues were removed to facilitate the felling of the concrete windshield which was dismantled in a piece meal small fashion with all dismantled concrete falling to ground inside the chimney for retrieval at the base.

Churchills used their in-house crane capabilities utilising Crane Appointed persons and Competent Slinger banksman to complete this phase of the job

The demolition of the concrete windshield started week commencing 15th June using Churchills specialist demolition rig and concrete cutting methodology which has been employed to demolish 2975m of reinforced concrete chimneys with wall thicknesses ranging from 150mm to 400mm

The 60m reinforced concrete chimney at the old Roche site in Welywn Garden City was reduced by 40m in only 20 days, the base 20m will be demolished using a high reach machine.

The reinforced concrete wall with an average thickness of 200mm was demolished with total efficiency using Churchills tried and test concrete cutting methodology.

Photographs depicting the chimney prior to the installation of our demolition rig are shown below.

To view a list of similar contracts completed by Churchills please visit our web site and go to our Demolition & Dismantling page and click on the PDF download.

Churchills Accreditation

A total of ten Churchill Steeplejacks operatives have successfully achieved the SSSTS accreditation for site supervision.

This level of commitment to training will ensure that all Churchill sites will have the construction industry requirement in relation to on site supervision. Add to this the following minimum requirement for a Churchill Steeplejacks (UK) Ltd site based team and our clients have arguably one the most highly trained and qualified workforces at their disposal;

The following are all managed by a team consisting of two NEBOSH in construction departmental managers

SSSTS
CSCS Industry Gold Card
CCNSG Passport to Safety
Quarry Passport
NVQ Level 2 Steeplejack/Lightning Protection Engineers
NVQ Level 3 Advanced Steeplejack
IPAF
Confined Space Working
NDT Dye Penetrant Testing
Abrasive Wheels
Mobile Towers
Safety Harness Inspection
PAT Testing
LOLER Equipment Testing
Appointed Person
Asbestos Awareness
Rescue & Recovery at Height
Slinger/Banksman
First Aid
Safe Earth Testing
Safe Road Digging

Concrete Chimney Refurbishment

A 60k project to refurbish 2no 45m reinforced concrete chimneys at The University of East Anglia has been completed within program and within budget by Churchill Steeplejacks (UK) Ltd

The project was completed over a twelve week period with a three man team in attendance and included the replacement and repair of the capping arrangements, concrete repairs to each windshield, lightning protection upgrade and the application of a protective paint system.

A steel support framework was also installed around the summit of both chimneys to provide structural support to the upper regions of each windshield.

The cold weather conditions experienced during January and February 2009 delayed the application of the paint product which required temperatures of 5 degrees and rising, following the completion of the contract the chimney windshields will remain free of maintenance for at least the next seven year period.

Steel Chimney Emergency Callout

A steel chimney located at Eastwood Comprehensive School in Nottinghamshire fell victim of the strong winds that hit the county during the earlier hours 23rd March 2009.

Churchills received an emergency call out request from the school who feared the chimney was in imminent danger of falling over, Churchills dispatched a three man team to site together with a mobile crane and successfully dismantled the chimney just in time to preventing it falling into classrooms below.

Once the chimney had been successfully dismantled Churchills then set about arranging for the manufacturer and installation of a temporary smaller chimney section to be fitted to the remaining base section of the chimney to ensure the school could continue to provide hot water and therefore remain open.

From receiving the emergency call all of the aforementioned work was safely completed within a 12 hour period.

This was possible due to Churchills possessing in house Crane Appointed Persons who were able to plan and manage the lifting operations with minimum notice coupled with our fabrication capacity.

These photographs depict the chimney in it's precarious position upon our arrival to site.

The importance of the inspection and maintenance of this type of insulated steel chimney has been recognised by the Health & Safety Executive who together with the steeplejack federation A.T.L.A.S have issued guidance notes detailing a thorough inspection criteria. Unfortunately whilst this particular chimney had been regularly inspected it would appear that the inspector had not completed the survey in accordance with the aforementioned recommendations.

SPECIALISTS IN HIGH RISE DEMOLITION & STRUCTURAL MAINTENANCE

In 2004 Churchill Steeplejacks (UK) Ltd were awarded the contract to complete the external refurbishment of a115m tall concrete cooling tower at Ratcliffe On Soar Power station.

Following the successful completion of the contract that saw Churchills provide, install and maintain all motorised access cradles and complete the contract with no sub contract element the contract was extended for the following four year period to include 6 of the 8no cooling towers at Ratcliffe on Soar.

Each cooling tower project involved up to 12 operatives working on a tower at any one time from the motorised access platforms suspended from the summit of the tower

One of the biggest challenges faced was how to ensure safe access and egress for all operatives working on the tower together with ensuring systems for effectively rescuing and recovering operatives within a twelve minute period from any position on the tower were in place at all times. This was successfully achieved via the deployment of a full time rope access team positioned on the scaffold at the summit of the tower.

Over 56000 man hours were engaged and in excess of 5000 temporary anchor locations were installed to complete the six towers, all being completed within program, within budget and most importantly without incident.

Suspended Access Platforms in operation

Installation of access scaffold around the full circumference

Churchill Steeplejacks Obtain CSCS Platinum Standard

Churchill Steeplejacks UK Ltd are the proud recipients of the CSCS Platinum Award that recognises a companies achievement in attaining more than a 90% ratio of it's workforce being CSCS accredited card holders.

Churchills have achieved the highest award available from CSCS with a 100% attainment level for it's employees with not one of the 40no cards being a minimum general workers accreditation and with all being industry related.

Boasting 2no NEBOSH in construction departmental managers, 12no SSSTS site based Operatives and one of only 2no NVQ level 3 Steeplejack assesors/trainers in the country this recognition by CSCS highlights further the companies passion for training it’s staff ensuring we possess the most highly trained, skilled and qualified workforce operating in our sector.

Pectel Group in Administration

The Pectel Group formed in 1982 entered into administration 12th December 2008 becoming Churchill Steeplejacks (UK) Ltd largest debtor since the formation of the company in 1994.

On the day Churchills completed extensive decommissioning work to the disused 45m concrete boiler chimney at the University Hospital Birmingham administrators Zolfo Cooper of Manchester were called in.

Formed in 1982 as an asbestos removal firm the growth of the Pectel Group saw them include no fewer than 12 Limited companies at the time they entered into administration with over 250 employees nationwide.