Workplace Safety: Panis Scenario
DO – CONTROLLING WORKPLACE SAFETY ISSUES (INTERNATIONAL)
UNIT ID3:
For: NEBOSH International Diploma for Occupational Health and Safety
Management Professionals
Guidance to learners
This assessment is not invigilated, and you are free to use any learning resources to which you have access, eg your course notes, or the HSE website, etc.
By submitting this completed assessment for marking, you are declaring it is entirely your own work.
Knowingly claiming work to be your own when it is someone else’s work is malpractice, which carries severe penalties. This means that you must not collaborate with or copy work from others. Neither should you ‘cut and paste’ blocks of text from the Internet or other sources.
The examination begins with a scenario to set the scene. You will then need to complete a series of tasks based on this scenario. Each task will consist of one or more questions.
Your responses to most of these tasks should wholly, or partly, draw on relevant information from the scenario. The task will clearly state the extent to which this is required.
The marks available are shown in brackets to the right of each question, or part of each question. This will help guide you to the amount of information required in your response. In general, one mark is given for each correct technical point that is clearly demonstrated. Avoid writing too little as this will make it difficult for the Examiner to award marks. Single word answers or lists are unlikely to gain marks as this would not normally be enough to show understanding or a connection with the scenario.You will have 4 weeks (20 working days) to complete the assessment.
Please refer to your registration confirmation email for the upload deadline.
Please note that NEBOSH will be unable to accept your assessment once the deadline has passed.
You must use the available answer template.
SCENARIO
Panis is a food manufacturer that specialises in baking and distributing breads. It mainly supplies bread to supermarkets. It has operated from a large purpose-built site for 30 years. On the site are the following buildings: a bakery (where the bread is made), a storeroom (for packaged raw materials) and a storage and distribution warehouse (for the finished bread products). There are also silos near the entrance to the site (for bulk raw materials). Overhead piping, beams, and fluorescent lighting run across the bakery’s low ceilings. The buildings are at the centre of a network of service roads crossing the site.
Normal operation
The organisation operates 24 hours a day, throughout the year. Workers are on a 2-shift rota system. The organisation employs 100 workers in various roles, such as office staff, production line workers, bakers, quality assurance staff, maintenance engineers, warehouse workers, and goods vehicle drivers. There are also trained first-aiders available on each shift.
The busy storage and distribution warehouse prepares for several pickups daily by the goods vehicle drivers, usually in the very early hours of the morning. There is a one-way system in operation for all vehicles across the site. Panis workers and visitors must use a separate entrance and exit from the goods vehicles and silo tankers. Workers and visitors have a separate dedicated parking area. There is a straight road with traffic calming measures, such as speed humps, running through the site.
Inside the warehouse, freshly baked bread is layered on pallets in steel racking. Racking is arranged in rows; each row is secured to the floor and is 10 metres (32 feet) long and 3 metres (10 feet) high. There are 8 parallel rows of racking, arranged in 4 back-to-back pairs. Aisles between each of the 4 pairs are narrow, with sufficient room to allow access for forklift trucks (FLTs). Sometimes the racking can become damaged when FLTs place the pallets on to them.
There are signs at the entrance to the warehouse prohibiting access to visitors. Within the warehouse, pedestrians must keep to a clearly-marked walkway, and all workers must wear hivisibility clothing and hard hats. At one end of the warehouse is the entrance to the manufacturing area, and at the other end, are several loading bays where the bread pallets are loaded by the FLTs onto large goods vehicles. Several danger signs are placed around the warehouse warning of moving vehicles.
Basic bread manufacture uses four main ingredients – flour, yeast, water, and salt. But the bakery also uses many other ingredients to make a range of different breads. The factory produces on average 200 000 thousand loaves of bread per day. The bread making process goes through several stages, and on average takes 4 hours per batch. The process uses many different pieces of machinery made from stainless steel. Some of the older machinery is critical to the bread making process. Once regular maintenance and cleaning has been carried out on a machine, this is indicated with a red-coloured tag.
Six electrically-earthed, vertical, 10 metre cylindrical steel vessels (silos) are each able to store up to 60 tonnes of flour and powdered sugar. Both ingredients are delivered in bulk 25 tonne loads, by silo tanker drivers via a dedicated road. Drivers are informed of the site layout before they arrive. Once the drivers arrive on site, they are expected to sign in and go straight to the unloading area. From here, the driver liaises with a bakery worker to unload the ingredient at a sheltered discharge point. The scheduled offloading operation usually takes around an hour. It uses a pneumatic conveying system, whereby compressed air (from an air compressor on the tanker) is used to dilute and blow the flour through connected pipework, directly to the main storage silo. This then passes through a coarsely painted steel cartridge filter into the main storage silo.
Silo tanker drivers often want the transfer done quickly, due to time pressures. Despite training and clear signage on how to perform the task safely, drivers tend to increase the flour transfer rate. More recently, when left unsupervised by bakery workers, some of the drivers have not always electrically earthed the tanker during unloading. Often, the drivers use the washroom facilities inside the warehouse before they leave. There is an old walkway, with faded markings, leading to the washroom facilities near the bakery. Bakery workers tend not to use these facilities as they are poorly lit and cross a busy route for FLTs.
Flour for immediate use is stored in a smaller, alloy steel receiving vessel inside the bakery. This receiving vessel is equipped with a fine mesh filter. Maintenance workers have reported that they are starting to find fragments of metal in this filter. When necessary, bakers top up the smaller vessel by pneumatically conveying flour from the main 60-tonne storage silo through transfer pipework. Recently, bakery workers have reported rattling noises inside this pipework and a slower flow rate in which the flour is being transferred. Several techniques have been used to try and free blockages quickly to allow production to carry on. It has sometimes been effective to bang the side of the blocked silo to dislodge the stuck material. Maintenance workers have also been known to insert a long pole into the maintenance hole at the top of the silo to try and free a blockage. On one occasion, entry was made using the internal ladder inside a silo that was three quarters full of flour. The maintenance worker stepped out onto the top layer of flour using a long wooden platform and tried to find and free the blockage, using a metal pole.
Other ingredients, stored in additional smaller silos inside the bakery, are vegetable oil and yeast.
From the vessel inside the bakery, the flour is pneumatically conveyed at high speed inside narrow steel pipework that runs horizontally and vertically along pipe racks, to the respective bread-mixing machines. There is evidence of some rusting within this pipework and blockages often occur during this process. There is a network of interconnected electrical bonding straps attached to the pipework and an earth grounding point. The humidity in the factory causes these bonding attachments to corrode. The bread mixing machines are positioned against an exterior wall closest to the vessel to minimise pipework length.
Ingredients are mixed at 360rpm for 4 minutes to produce a dough. The dough from the mixer (and often, some unmixed flour) is tipped out onto an adjacent stainless steel conveyer belt, and is cut and shaped into evenly-sized balls. The dough balls are then dropped into individual baking tins and move along the conveyer to a proofing oven, held at about 45°C (proofing is a process that activates the yeast and causes the bread to rise and expand). After proofing, they are then moved along the conveyer through an oven. After the bread is baked it moves to quality assurance. A suction machine then removes the bread loaves from the tins and each loaf is allowed to cool. Once the bread has cooled it is sent down the conveyer to be sliced, packaged, and stored in the warehouse ready for distribution. Due to the heat produced in the bakery, bakery workers sometimes keep an external door open for some fresh air.
A separate, large storeroom holds smaller quantities of packaged ingredients such as nuts, seeds, and speciality flour. Speciality flour is stored in 25kg sacks against the back wall of the storeroom. Speciality flour is manually emptied from these sacks into mixing machines, with the empty sacks being flattened or folded ready for disposal.
The factory has several old dust extractors (local exhaust ventilation (LEV)) which are overdue for servicing. Although there is a policy for weekly visual checks on the LEV performance, these checks rarely happen due to a lack of trained workers. Some bakery workers have noticed flour leaking from the LEV into the bakery.
Excess flour on floors and steps is manually swept up at the end of each shift. The proximity of certain machinery to each other and to exterior walls makes thorough cleaning difficult and time consuming.
FLT use in the storage and distribution warehouse
Battery-powered counterbalance FLTs are used to move packaged materials in and around the warehouse, and into large goods vehicles outside, in all weathers. Each FLT is fitted with an automatic, audible reversing alarm. The FLTs are charged at a dedicated battery charging station inside the warehouse. They are returned to this point for recharging when required. This area is equipped with mains electricity, compressed air, and water services. There are posters next to the charging station, giving reminders about safe use of FLTs on the site.
Some parts of the FLT route contain potholes and, despite suitable training received, CCTV has shown some of the drivers often treating the working area like a racing track. Most of the drivers keep the forks raised when moving loads. There is historic evidence of discarded loads and broken pallets along the FLT vehicle routes. Workers regularly have to clear loaves of bread from these routes. Drivers sometimes travel sideways across a slope if it will save them time. The treads of the pneumatic tyres are worn smooth and the speed at which the drivers corner around sharp bends (sometimes with elevated loads) often causes the FLTs to lose control.
Loading bays
Outside the storage and distribution warehouse, there are 5 loading bays, where bread is loaded onto a variety of goods vehicles (some of which have separate trailers) using the FLTs. The FLTs enter through the rear doors of a trailer, deposit the pallets, and reverse out. After loading, the FLTs return to the warehouse. Each bay entrance is fitted with a plastic curtain and, in front of that, a roller shutter door. On arrival, goods vehicle drivers are expected to hand in their vehicle keys. Within each loading bay there is a safe area for the goods vehicle drivers to stand while the bread is loaded onto the goods vehicles. Outside, separated by bollards, there are dedicated parking bays for goods vehicles to wait.
Accidents
Maintenance accident
Two trainees were assisting two qualified maintenance engineers during a quiet period of the shift. They were carrying out an in-house routine maintenance activity on an electrically-powered conveyer that was usually in 24-hour operation. The conveyor had been electrically isolated using a Lock Out, Tag Out system, and allowed to cool for almost 2 hours. Barriers were erected around the machinery, as well as signage to warn of the maintenance activity. One of the maintenance engineers asked the two trainees to remove the conveyer motor for cleaning. The trainees proceeded to do this, while the maintenance engineers were called away on another job. Once the electric motor was removed, the trainees decided that it needed replacing due it its condition and age. The correct model was collected from the spare’s storage room (no permit-to-work (PTW) system or equivalent safe system of work (SSoW) was in place to authorise this). Neither of the trainees had done this type of work unsupervised before. However, using the equipment manufacturer’s manual as a guide, they felt confident enough to carry out the task safely. The conveyer was required to be back in service as quickly as possible, so they had to rush to get the job done. Some of the guards around the machinery’s gears and chains were removed to provide better access. When the job was completed, neither of the trainees had noticed that they had failed to reinstate the machinery guards. Locks, tags, and signage were removed, and the power switched back on.
The next day a bakery worker’s clothing was caught in the conveyor belt motor mechanism. The worker reacted quickly, pressing the emergency stop button, but it did not stop the conveyer. The worker was seriously injured as a result.
A subsequent investigation identified that the guarding was missing. It also identified some electrical faults. These faults resulted in a further shutdown of the conveyor to effect repairs.
Dough-mixing accident
In another accident, a worker had been adding speciality flour and nuts by hand into a dough mixing machine. The dough was being mixed by a paddle attachment. The lid, on top of the machine in a closed position, had a gap of approximately 8 centimetres. The worker lifted the lid to tip the extra ingredients in while the machine continued mixing. The worker’s glove had fallen into the mixing bowl. They immediately reached in to retrieve their glove and suffered two fractured fingers.
Explosion
The latest accident was a catastrophic dust explosion in part of the bakery that injured 20 workers. Independent reports suggested that it consisted of a primary explosion, quickly followed by a more severe secondary explosion.
Part of the factory building was so badly damaged that the structure will need to be demolished.Task 1: Dust explosions
1
One of the conditions for a dust explosion is that there must be an ignition source.
(a)
Based on the scenario only, give examples of possible ignition sources that might have led to the primary dust explosion in the bakery.
(6)
(b)
What other conditions must have existed in the bakery for the primary dust explosion to occur?
(10)
Note: You should support your answer, where applicable, using relevant information from the scenario.
(c)
What conditions must have existed at the bakery for the secondary dust explosion to occur?
(6)
Note: You should support your answer, where applicable, using relevant information from the scenario.
(d)
What control measures could the bakery have used to minimise the risk of a secondary explosion?
(12)
Note: You should support your answer, where applicable, using relevant information from the scenario.
Task 2: Causes of instability of an FLT
2 What are the causes of instability of FLTs used in the storage and distribution warehouse?
Note: You should support your answer, where applicable, using relevant information from the scenario.
(12)
Task 3: Maintenance
3 (a) Based on the scenario only, what went well with the recent routine maintenance activity on the electrically-powered conveyor?
(8)
(b) Based on the scenario only, what did not go well with the recent routine maintenance activity on the electrically-powered conveyor?
(10)
(c) Comment on what should have been considered when deciding on the frequency of a maintenance programme at the bakery.
Note: You should support your answer, where applicable, using relevant information from the scenario.
(15)
Task 4: Demolition
4 The part of the bakery damaged by the explosion is due to be demolished.
The rest of the bakery will still be in operation.
(a) What should be considered in a pre-demolition survey for this site?
Note: You should support your answer, where applicable, using relevant information from the scenario.
(15)
(b) What arrangements should be in place to protect Panis workers before and during the demolition work?
Note: You should support your answer, where applicable, using relevant information from the scenario.
(15)
Task 5: Transport management
5 (a) Based on the scenario only, what are the positive aspects of traffic management inside the storage and distribution warehouse?
(5)
(b) What are the positive aspects of traffic management around the rest of the site?
Note: You should support your answer, where applicable, using relevant information from the scenario.
(10)
(c) What improvements could be made to the existing traffic management arrangements in the warehouse?
(8)
(d) What are the loading hazards that should be considered in a workplace transport risk assessment for this warehouse?
Task 6: Silo cleaning
6 (a) What should have been considered when assessing the risk before entering the bulk flour silo to free blockages?
(12)
Note: You should support your answer, where applicable, using relevant information from the scenario.
(20)
(b) Assuming that entry could not be avoided, how could the risks have been controlled before and during this activity?
Note: You should support your answer, where applicable, using relevant information from the scenario.
(20)
Task 7: Controlling static build up
7 (a) Comment on how effective Panis is in controlling static build up.
Note: You should support your answer, where applicable, using relevant information from the scenario.
(12)
(b) Based on the scenario only, how could static electricity control be improved?
Task 8: Operation of mixer
8 (a) How would an interlocking guarding system operate to help avoid the dough mixer accident?
(10)
(3)
(b) Apart from guarding, what other working practices could have minimised the risks for the dough mixer worker when operating the mixer?
Task 9: Work at height
9 The top shelf of one of the racking bays has been badly damaged by an FLT and requires urgent repair. Adjacent racking is still in use for storage.
(7)
What should be considered before starting the repair?
Note: You should support your answer, where applicable, using relevant information from the scenario.
(14)