Five ways trapped key interlocks protect tanker loading and unloading

Loading and unloading tankers carries significant risk. Procedures are often complicated, particularly when earth lines and valve systems are involved. Drivers have to consider variables such as load characteristics, the frequency of vehicle movement and the number of products to be loaded or unloaded.

Potential issues include:

• “Drive-aways” while tankers are connected to equipment or damage to extended gantries;
• The wrong substance being loaded or unloaded;
• Shortcuts being taken and steps in safe loading missed, such as earth line connections being made or hoses returned;
• The danger of loading or unloading hazardous or flammable substances;
• Product spillage;
• The environmental impact of product release.

Loading and unloading tankers carries significant risk

Trapped key interlocks (TKIs) provide specific protection and risk control in these types of application. TKIs encode procedures to ensure that systems can only operate one way: the safe way. Depending on the application, TKIs typically control five main risks:

1) They immobilise vehicles while loading and unloading is taking place by using an airline interlock or interlocking existing barriers. This prevents a “drive-away” while equipment is connected.

2) For multi-step processes, they force drivers to always follow the correct procedure and avoid shortcuts.

3) They ensure that valves can only be operated when it is safe to do so.

4) They make sure the correct substance can only be delivered or received by the appropriate tanker.

5) As primarily mechanical devices, they do not pose an ignition-source risk in hazardous areas.

Designing an effective TKI-controlled tanker loading system requires a clear understanding of the procedure involved and the equipment to be included in each stage of the process. This should be carried out in conjunction with a thorough risk assessment of the process itself.

By: David Hughes, Sales Director, Castell Safety International Ltd.

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Industrial safety: the true cost of cost-saving

Reducing costs is a priority for businesses around the world. The traditional view of safety is that it reduces efficiency and costs too much to implement. If safety devices are susceptible to environmental degradation and can be defeated, so the thinking goes, do they have any real value?

In fact, creating a well-designed safety system for a specific operation can have a positive impact on both productivity and costs.

New sentencing guidelines for serious workplace incidents in the UK will come into force in early 2016

There are five separate steps to achieving operational gains and cost savings.

1)    Implement a safety system for the lifetime of the equipment

Ensuring that a safety system is designed for the life of the equipment can reduce maintenance and running costs significantly. Trapped key interlocks have proven over decades that they are durable and robust, particularly in harsh or difficult environments.

2)    Reduce the number of electrical connections

Production managers in industries such as food and beverage confirm that electrical devices have a major impact on downtime, especially after washdown cycles. Mechanical safety systems, such as trapped key interlocks, reduce the number of electrical connections and therefore the number of potential failure points. Removing the need for extensive wiring looms also reduces the initial machine cost.

3)    Design the safety system in harmony with the operation of the equipment

Designing a safety system that safely encodes the operational process of the machinery will reduce variance produced by individual operators running the equipment in different ways. In effect, the safety system can ensure that human variance is removed.

4)    Implement robust safety measures

Operators will try to bypass safety systems, so it is important to ensure that the chosen system is durable enough to withstand such attempts. Preserving both the safe working of the system and the correct operation avoids the cost of potential accidents and prevents the adoption of unsafe processes.

5)    Understand the true cost of ignoring safety requirements

The financial burden of investigations, fines and damages increases every year as legislation and its policing become more stringent.

New sentencing guidelines for serious workplace incidents in the UK are due to be published on 3 November 2015 and will come into force in February 2016. Courts are likely to hand out an increasing number of custodial sentences to convicted individuals, with a minimum of 26 weeks in prison proposed for those guilty of committing offences considered within the highest category of harm i.e. death, high risk of death or catastrophic injury. Organisations labelled large (with a turnover of more than £50m) could receive fines of up to £20m. The tariff for very large companies (whose turnover “very greatly exceeds” £50m) has not been set, but the guidance states “it may be necessary to move outside the suggested range to achieve a proportionate sentence”. Experts believe that fines of £100m are not beyond the realms of possibility.

 

So the most economical way to approach safety is to

                • embrace the requirements early;
                • carry out thorough risk assessments;
                • design in the safety system as early as possible.

This approach maximises operational efficiency and plant uptime, and reduces risk.

By: David Hughes, Sales Director, Castell Safety International Ltd.

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Loading dock safety: what do you need to consider?

The risks

The risks posed by loading dock operations can vary dramatically from site to site, and even from bay to bay, depending on the specific circumstances involved. As with other areas of the business, the risks need to be determined by regular assessments before safety plans are developed.

The risks posed by loading dock operations can vary dramatically from site to site

There are six common causes of accident in the loading dock area:

  • Falls from height
  • Movement of vehicles
  • Goods strikes
  • Automation equipment
  • Loading bay pull-offs / drive-aways
  • Uncontrolled loading bay access

Other factors to consider include:

  • Security
  • Pest control
  • Efficiency
  • Environmental impact
  • Traffic flow

 

Practical considerations

A wide range of loading bay variables will influence the choice of safety solution proposed. These include:

  • Vehicle mix – fixed-bed, semi-trailer or articulated vehicles;
  • Door type – manual or automatic;
  • Door construction – sectional, up-and-over / vertical lifting or roller shutter;
  • Loading bay equipment – lights, traffic lights, levellers, air cushions;
  • Single- or double-height trailers;
  • Communication between drivers and loaders – physical barriers, languages, noise, access points;
  • Temporary and third-party personnel;
  • Training and knowledge.

 

Safety solutions – What is common practice?

Generally, sites operate a procedure-based system with different levels of sophistication, which all require management intervention. One or more of the following safety precautions will be present:

  • Nothing
  • Traffic lights
  • Leaving the driver’s keys in the office
  • Hanging the driver’s keys on the loading bay door
  • Banksmen / traffic marshals
  • Simple wheel chocks
  • Experience

 

What are the benefits of engineered solutions?

Engineered solutions isolate the potential hazard by immobilising vehicles while loading takes place. The method of restraint differs between solutions, but each restraint will:

  • Enforce loading procedures;
  • Remove the risk of error;
  • Reduce the dependence on verbal communication for safety;
  • Provide feedback on usage;
  • Improve efficiency;
  • Improve security;
  • Protect assets and personnel.

 

 Implementing a safe system

There are a number of steps to follow to establish a safety system that is reasonable and practicable:

By: Jason Reed, UK Sales Manager, Castell Safety International Ltd.

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How trapped key interlocking protects workers at HV substations

Interlocking switchgear within HV substations ensures that personnel operate equipment safely, according to the correct procedures. Using a well-designed trapped key interlocking scheme will prevent personnel accessing potentially dangerous areas before the switchgear system has been put into a safe condition.

A good interlocking scheme will also ensure that the system functions correctly, so that there is no chance of, for example, switching two incoming feeds onto a common bus bar. This protects the equipment from damage and greatly reduces the risk of fire or arc flash.

A well-designed trapped key interlocking scheme will prevent personnel accessing potentially dangerous areas before the HV switchgear system has been put into a safe condition

There are four ways trapped key interlocks (TKIs) protect HV substations and their operators:

  1. Many HV substations are located in remote, unmanned sites which can attract attempted unauthorised access. TKIs help to safeguard this kind of vulnerable equipment.
  2. TKIs intended for HV substations have a proven design life of 45 years, allowing the safety devices to perform through decades of operation.
  3. Trapped key interlocking enforces the correct operation of equipment and therefore protects the continuity of supply.
  4. TKIs ensure that part of a system is isolated and correctly earthed before maintenance can be carried out on that section.

By: Adam Felton, Technical Marketing, Castell Safety International Ltd.

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Switchgear and protection: trapped key interlocking vs LOTO

There are two potential options when considering a mechanical safety system for switchgear applications. The choice is between a trapped key interlocking system or a padlock-based lock-out / tag-out (LOTO) system. Both systems:

  • Provide a method of isolating switchgear.
  • Allow safe personnel access when maintenance of machinery is required.
  • Are available in full stainless steel or brass versions.
  • Offer a comprehensive range of products with different forms and sizes to suit the needs of the equipment concerned.

However, in terms of safety, trapped key interlocks (TKIs) offer significantly higher levels of protection compared with LOTO.

Trapped key interlocks safeguarding a switchgear installation

This is due to the four reasons given below:

  1. TKIs are durable with a proven track record of withstanding harsh operating environments through decades of operation.
  2. TKI’s force workers to follow a strict process which prevents them from deliberately skipping or inadvertently missing steps. The equipment is interlocked together in such a way that steps cannot be overlooked or ignored.
  3. In an environment where staff may be unfamiliar with operations and speak a range of different languages, the enforced procedure of TKIs negates miscommunication or misunderstanding of operating practice.

    Misunderstandings are a risk when staff speak a range of different languages

  4. When there is a need for full-body access, TKIs provide a personnel key that protects workers from potential danger and puts them in control of the process. Until the personnel key is returned, the switchgear cannot be returned to the live state.

By: Adam Felton, Technical Marketing, Castell Safety International Ltd.

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How trapped key interlocking protects switchgear workers

The ability to work across HV, MV and LV switchgear means that a trapped key interlocking system can be used as a single solution to provide personnel safety and ensure equipment is used in the correct way.

Major switchgear manufacturers recognise the safety benefits that trapped key interlocks provide

Major switchgear manufacturers recognise the safety benefits that trapped key interlocks provide and design equipment to be able to accept this safety technology across their own breakers, isolators, switch disconnectors and earth switch mechanisms.

When used with switchgear, a well-designed trapped key interlocking scheme:

  • Forces operators to follow a predetermined switching schedule. This ensures the safe operation of switchgear and eliminates the risk of human error while switching between supplies.
  • Allows less-skilled operators to be able to switch between supplies comfortably as they are forced to follow a certain switching schedule, which enforces the safe operating process.
  • Protects workers by ensuring that personnel cannot access potentially dangerous areas without the switchgear system being put into a safe condition.

Trapped key interlocks provide a high level of safety for both operators and equipment as the operating procedure has to be strictly followed and cannot be circumvented.

By: Adam Felton, Technical Marketing, Castell Safety International Ltd.

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How trapped key safety systems make cement mixing more efficient

Concrete production is big business in the UK, with around 1,000 ready-mix sites and a large number of facilities producing precast concrete structures. In these environments fast, safe access to the mixer is important as set concrete can easily cause blockages if not regularly washed down.

Fast, safe access to the mixer is important as set concrete can easily cause blockages if not regularly washed down

The World Business Council for Sustainable Development’s ‘Health and safety in the cement industry: Examples of good practice’ recommends that when access to hazardous areas is required during normal operation, interlocking guards should be considered the number one safety option. Regulation 11 of the HSE’s ‘Provision and use of work equipment regulations 1998 (PUWER 98) (ACOP 2008)’ suggests fitting interlocked guards to protect operators from the dangerous parts of machinery.

There are three main ways trapped key interlocking systems can provide an efficient safety solution for the cement mixing industry:

  1. Trapped key interlocks ensure operators follow a strict procedure.
  2. Isolation of the power supply can be coupled with a motion-monitoring device which grants access to the mixer as soon as safely possible. In contrast to fixed-time delay systems, which can overcompensate rundown times for lighter loads, a motion-sensing system reduces downtime for equipment with variable rundown speeds.
  3. Trapped key interlocks are highly durable, have a longer product life and require less maintenance than alternative safety systems. As a result, the machinery to which they are fitted suffers less downtime and so overall plant utilization is increased.

The robust mechanical nature of the locks and keys is well suited to the harsh environment of a concrete plant, as well as being resistant to regular wash downs.

By: James Seel, Marketing Assistant, Castell Safety International Ltd.

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Two ways trapped key interlocks can help to achieve Target Zero in the quarrying industry

The HSE describes quarrying as “one of the most dangerous industries to work in”. Nearly 3,500 UK workers have suffered an injury reportable to the HSE since 2000, a figure that includes 29 fatalities.

Trapped-key interlocks are particularly suited to the quarrying and aggregates industries

Between 2000 and 2010, the Hard Target initiative led to a reduction in RIDDOR-reportable injuries in quarries by 76%. The initiative involved collaboration between the HSE, trade associations and industry representatives. These three groups make up the membership of the Quarries National Joint Advisory Committee (QNJAC).

At Hillhead 2010, Judith Hackett, Chair of the HSE, congratulated the industry on the improvement in safety Hard Target had achieved, and introduced Target Zero, a continuation of the drive to reduce injuries in the quarrying sector.

Target Zero is the industry’s pledge to reduce injuries by a further 15% year-on-year from 2010 until 2015. All the major players in the quarrying industry have pledged their allegiance to Target Zero, implementing their own internal strategies to achieve the target reduction in injuries and improvement in safety. These efforts have led to a reduction in the lost-time injury frequency rate (LTIFR) reported by the principal quarrying companies in recent years. LTIFR is the main internal indicator of the performance of these firms against their own zero harm targets.

The HSE’s Approved Code of Practice and guidance document ‘Health and safety at quarries – Quarries Regulations 1999’ recommends that interlocks should be included in any risk inspection scheme. Trapped-key interlocks are particularly suited to the quarrying and aggregates industries for two main reasons:

 

Durability

The quarrying sector has a fatality rate 12 times higher than the all-industry average. Any safety solution must be robust and durable, as the harsh working environment places severe demands on both operators and machinery. Trapped key interlocks are resistant to wash-down and cleaning regimes. Figure symbol interlocks are particularly beneficial as, unlike tumbler mechanism locks, their normal operation won’t be compromised by plugged dirt or other substances.

Maintenance

Regular maintenance is required to keep machinery functional, but each round of maintenance introduces a safety risk as access to dangerous parts of machinery is sometimes required. The desire to minimise downtime means the maintenance process needs to be as safe and efficient as possible. Trapped-key technology ensures that the correct procedure is followed every time, improving safety and maximising productivity.

By: James Seel,  Marketing Assistant, Castell Safety International Ltd.

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Seven reasons to choose safety interlocks for MV and LV switchgear systems

The risks surrounding the operation of electrical switchgear systems are defined in detail and mitigating these is an important aspect of any health and safety policy. As set out by regulatory bodies like the HSE, in publications such as Electrical Switchgear Safety (INDG373), there are a number of important factors to consider. These are well documented and include:

  • Providing the correct training;
  • Ensuring regular maintenance;
  • Ensuring staff know the rules and their responsibilities;
  • Carrying out regular risk assessments and acting on their findings.

Each switchgear system will have its own set of operational and maintenance requirements, and it is important these are taken into consideration before implementing a safety solution.

The use of trapped key technology to ensure the safe operation of electrical switchgear systems has been established since the early 1920s. There are two principal issues that interlocking provides a solution for: the correct operation of switchgear equipment – reducing the possibility of arc flash – and the provision of safe access during maintenance.

Trapped key interlocks offer seven distinct advantages when used to safeguard MV and LV switchgear systems:

  1. They prevent personnel from accessing live terminals and cabinets.
  2. They protect equipment by ensuring it can only be operated safely.
  3. They can be operated by less skilled personnel, reducing training costs.
  4. They can reduce unintended outages caused by incorrect operation.
  5. They perform in harsh environments.
  6. They deliver a solution that satisfies the higher global MV standard IEC/EN 62271-200, defined as ‘accessible and interlocked’ as opposed to ‘accessible by procedure’.
  7. They allow the integration of LV and MV switchgear systems, different manufacturers’ equipment, and subsystem elements such as breakers and transformers.

Each switchgear system will have its own set of operational and maintenance requirements, and it is important these are taken into consideration before implementing a safety solution. In general, trapped key interlocks are highly flexible and provide integrated and retrofit solutions across a wide range of manufacturers’ equipment.

By: David Hughes, Sales Director, Castell Safety International Ltd.

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Plant maintenance and safety interlocks – myths and facts

In a recent article entitled “Unsafe Maintenance”, Judith Hackitt, chair of the UK’s Health and Safety Executive, examined some of the reasons why so many serious accidents and even fatalities continue to occur within processes related to the maintenance of machinery and equipment.

Trapped key interlocks ensure that machinery is maintained in a safe and efficient manner

Judith identified several common attitudes, concerns or faults which can ultimately lead to the safety of maintenance workers being compromised:

  • Time pressure – while machinery is stopped, money is being lost.
  • A focus on addressing everyday risks such as slips and trips, rather than mitigating the potential risks involved in machine maintenance.
  • A failure to plan maintenance activities or consider the best and safest ways to carry them out.
  • A perception that safety equipment will slow down production.
  • An absence of basic safety equipment, such as lockout / tagout and “Castell key arrangements”, which prevent access to running machinery and accidental start-up during maintenance activities.
  • A lack of the necessary ability to safely maintain equipment.

 

Trapped key interlocks can address all of these issues. It would be helpful to challenge some of the common industry misconceptions and separate fact from fiction.

“Mechanical trapped key interlocks slow down production; sensor-type safety solutions are much faster and just as safe.”

MYTH – A well designed safety interlocking system will work in harmony with existing manufacturing processes.

 “A well designed trapped key interlock can ensure the highest levels of safety integrity.”

FACT – The secret to a good safety system is a comprehensive risk assessment and understanding of the maintenance requirements. Trapped key technology will enforce these procedures.

 “I have to choose between implementing a trapped key system or a lockout / tagout system.”

MYTH – Trapped key interlocks and lockout / tagout can be combined to deliver an integrated safety system that covers planned and unplanned maintenance intervention.

 “Trapped key interlocks are expensive and inflexible.”

MYTH – With a wide installed base, trapped key interlocks have a long heritage of flexibility across heavy and light manufacturing operations. They are often found in excellent working condition even after decades of use, providing years of cost-effective safety.

“Interlocks are complicated and confusing.”

MYTH – Being process-driven, trapped key interlocks are easy to use, regardless of language or technical expertise.

 

Allied to thorough risk assessments and clear method statements, trapped key interlocks ensure that machinery is maintained in a safe and efficient manner by:

  • Dramatically reducing process risks and enforcing routines.
  • Isolating a machine’s power supply before work can begin.
  • Creating a robust process in areas where noise and communication could be an issue.
  • Performing in harsh and difficult manufacturing environments.

By: David Hughes, Sales Director, Castell Safety International Ltd.

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