SIM 03/2009/17
A number of paper mills have been seeking additional information following the publication of Making Paper Safely (MPS) last year. As a result, a working group of the Paper and Board Industry Advisory Committee (PABIAC) met recently to discuss the key issues and questions that have arisen around the industry and to try to provide some simple answers. The questions and relevant page numbers for answers are set out below.
It is in everyone's interest to promote understanding of the issues and PABIAC will publish further question and answer sheets on MPS if there is a demand. If you do have any further questions that you would like answered please contact the CPI, your Trade Union or HSE, via your local inspector. We would be pleased to help.
Question 1. When is access to the machine on the run permitted?
It is not. With efficient operation and the right choice of guarding there should be no need to access to the machine while it is on the run. Many mills have made substantial improvements to the operation of their machines, reducing breaks, and achieving better feeding. When the process is efficient, guarding is not an obstacle.
Remember that the crawl facility is not 'safe'. It is a compromise that needs to be backed up by a safe system of work, which is tightly controlled and put into practice without fail.
Question 2. When is an interlocked guard permissible (the hierarchy of guarding states fixed guards are better than interlocked, however it is much easier to remove a fixed guard whilst a machine is running than to defeat an interlocked guard)?
There is no simple, single answer to this and no exhaustive list, hence the examples and illustrations in Making Paper Safely (MPS). The law is structured to allow sufficient flexibility for local variations. If there were lists specifying when certain safeguards should be used they would be out of date as the ink dried. The way mills achieve the standard is their choice. What this means is that mills must have the competence they need available to apply basic principles, the law and industry guidance properly and make a judgement based on a whole host of factors. Mills should be able to explain the reasoning behind any decision and justify the safeguarding arrangement selected.
Many mills are succeeding in meeting MPS and some have come up with innovative solutions that have included changes to their process, with substantial financial as well as safety benefits. It can be done.
The type of safeguard selected will depend on the following factors (given in no particular order):
The standard BS EN 1050: 1996 has a useful summary, which says, 'You must ensure that the safeguarding selected is of a type that, by experience, provides a safe situation for the intended use and is appropriate in terms of the probability of defeat or circumvention, severity of harm and hindrance to the execution of the required task.' Flowery language, but it makes the purpose clear.
If, as the question implies, you know that at a particular part of the machine people are likely to circumvent the proposed guard, by taking it off and leaving it off, because of the frequency and nature of the access (we are back to where do people go and what do they do when they get there) then clearly the fixed guard might not be the most suitable safeguard.
It might be helpful to provide clear definitions of what we mean by fixed and interlocking guards (Note: there are a number of other guards, but we see no value in simply writing out whole standards and definitions).
Fixed guards are defined in BS EN 953: 1998 as a 'guard kept in place (i.e. closed) either permanently e.g. by welding or by means of fasteners i.e. screws, nuts etc. making removal/opening impossible without using tools.'
These can be used for those parts of the machine where frequent access is not required. Note that closed means 'kept in place' for a fixed guard. They have commonly been used at the wet end to guard the underside of the wire and wire pit. Fixed guards that can be in position while not 'closed' (i.e. they effectively become lift off guards or simply open on hinges) do not meet the requirement of the definition. An example of this would be where a fitting on the machine includes a bolt. The guard is hung on that bolt prior to a nut being fixed in place. If the nut were not fixed the guard could be left not 'closed'. In contrast if the guard had to be held in position while a bolt was inserted and fixed in place that would satisfy the definition, as the fitting would not permit the guard to be hung in position while it was not 'closed'.
Interlocked guards are defined in the same standard above (and in BS EN 292: 1991) as a 'guard associated with an interlocking device so that: the hazardous machine functions 'covered' by the guard cannot operate until the guard is closed; if the guard is opened while hazardous machine functions are operating, a stop instruction is given; when the guard is closed, the hazardous machine functions 'covered' by the guard can operate, but the closure of the guard does not by itself initiate their operation.' These are used where frequent access is required. They have been commonly used for the front side dryer section.
A subsidiary question arose here ‘What is meant by frequent access?’
BS EN 953 defines frequency of access as 'number of occasions on which access is required or foreseeable within the guarded area per unit of time.' We could select an arbitrary frequency, but it is not likely to be helpful. This standard does suggest an example of high foreseeable frequency of access as more than once per shift. Certainly HSE would challenge any mill where a guard was removed 1 per shift. We would suggest mills look at what people do on each machine and how frequently they do it and build up a scale of frequency, which could be used as a guide. Remember this should include changes in frequency where foreseeable access is required due to known problems that arise at certain parts of the machine.
Question 3. What are the guard requirements when it is possible to climb behind the guarded area or stand inside the guarded area?
The answer to this lies in the selection and design of the safeguards. Bearing in mind the advice given above it is likely that a combination of different guards and guards with devices would be appropriate on any given machine. Guards should be selected from the following in the order of priority given (based on the guidance given in BS EN 953: 1997 Para 6.3 and the Provision and Use of Work Equipment Regulations 1998);
1. Local guards, which enclose individual hazards if the number of these is low. This can provide an acceptable residual risk and permits access to non-hazardous machine parts for setting, maintenance or adjustment.
2. Guards that enclose all hazards if the number or size of these are high. In this case setting, maintenance or adjustment points should be located outside the guard as far as possible.
3. A partial distance guard, if the use of an enclosing guard is impracticable and the number of hazards is low.
4. Fully surrounding distance guard, if the use of an enclosing guard is impracticable and the number and size of hazards is high.
Local guards may not be suitable where people can walk into the machine and then reach the hazard. An example would be at the lower levels of felt runs. However, such guards might be required at interchanges between sections.
There is no hard and fast distance between the face of the machine and the guard that we can specify as 'acceptable' to prevent full body access. On some machines the presence of service pipe work and other returns or structures mean that, despite a gap of 200mm between the machine face and the guard, it would be extremely difficult for a person to stand and carry out any task behind in the guarded area with the machine running. No one is suggesting that distance guarding (either fixed or interlocked) cannot be used. What we would suggest is that mills should not make the assumption that distance guarding is the first choice of protection without going through the process of considering the hierarchy and producing a reasoned justification for whatever safeguarding is selected. It would appear that there has been a focus on the standard BS EN 294: 1992 (now replaced by BS EN ISO 13857:2008) with less regard to other standards and guidance.
The risk of people climbing on or over guards should be reduced by selection of enclosing guards where practicable, and secondly by design. This means for example ensuring they are sufficiently high, and/or eliminating horizontal members and the horizontal components of mesh from the outside surface of the guard to make climbing difficult (e.g. fences on cross machine walkways).
Question 4. Are nip guards required as a secondary guard under hold to run situations?
No. The safeguard is the guard that encloses all the hazards. Further down the hierarchy access can then be made using a hold to run facility (the assumption is made that this is at crawl only) as part of a safe system of work. This is an example of a combination of safeguards to achieve adequate control of the risk.
Question 5. When is hold to run acceptable? particularly when fitting dryer ropes there is a need to run the machine with people feeding the new rope, so would crawl by hold to run with the guards open be acceptable?
It is acceptable when it is the highest level of risk control that can be achieved. As soon as the guard is opened operation should be limited to hold to run. If there is no other means of carrying out this task, then access can be made using a hold to run facility as part of a safe system of work.
Question 6. Do the edges of felts and wires only require guarding when it is possible for the edge to cut the throat and face area?
MPS states that you should 'provide guarding to prevent people coming into contact with the edge of the wires, particularly at head and neck height.' The guidance therefore indicates that while it is preferable that the edge of the wire is guarded, it becomes a significant hazard when the head and neck are exposed to possible injury.
Question 7. What is the view concerning the use of light beams and pressure pads in addition to front face and rear face guarding?
There are concerns about the reliability of the existing technology of light beams or pressure pads in the harsh environment at the front and back of the papermaking machine. However, such technology might be suitable in other areas, such as the reel up. The application of electro-sensitive protective devices (ESPDs) using light curtains and light beam devices is complex. Positioning and the interface with the machine control system need to be carefully designed and installed. The monitoring, inspection, and testing regimes can be more demanding than those for more traditional guard solutions.
Question 8. Rotating shaft guarding - Do all shafts and roll ends etc. need to be guarded even if there is no protrusion that could snag?
This is best answered with an example. Some pump shafts become corroded and wet and it is foreseeable that people will be near such parts while handling tools. It is foreseeable that clothing or a tool could snag on a corroded surface and a person could be injured. Where this is the case the shaft should be guarded. The same principle would apply to similar situations.
Question 9. When is competence a sufficient control measure (i.e. can a trained craftsman remove a fixed guard with the machine running to carry out some tasks in a similar way (e.g. To take wire tension readings)?
See the answer to question 1. Access for wire tension readings has been achieved in mills by provision of openings in fixed guards (that conform to safety reach distances), and by design of openings in guards on walkways that permit access while preventing the possibility of the person taking the readings falling onto the wire. Mills do need the potential process efficiencies gained from this monitoring and the success of many mills in dealing with this makes it clear that it should not be necessary to prohibit such inspection and testing.
Reliance on training, instruction, information and supervision is at the bottom of the hierarchy. Guards should be designed to take account of the need for such inspection or testing and automated systems for scanning should be considered. It is not acceptable for a person to override or defeat the guard in the way the question describes.
Truly exceptional situations that are strictly defined and managed might arise when those with specialist knowledge and competence, such as engineers, need to carry out work, for example diagnostic testing, which cannot under any circumstances be done with the machine stopped or guards in position. This would not include routine access such as felt inspection and testing or routine maintenance. The law requires that such situations be assessed and the risk reduced by the provision of a combination of measures. This would include temporary guards and limits to the power, speed and range of movement of hazardous parts.
Question 10. What is the position regarding press crawl speeds when there is no operator intervention?
If the press is fully guarded and there is no operator intervention, then there is no risk.
Question 11. Could the requirements relating to the emergency stop and speed control systems and pre start warning device set out in paragraphs 41-43, and 45-47 be clarified?
Several issues have arisen concerning this section of MPS, which were not raised during the consultation period. A specialist has been asked to carry out further research into the issues raised and the outcome will be circulated as soon as it is available. (See paragraphs 10-15 of the main body of this SIM for details of the results of the work undertaken by HM Specialist Inspectors.)
Question 12. What is the position regarding line shaft driven machines; in particular the splitting of the line shaft and provision of separate drives?
The main problem appears to be the need to provide interlocked guarding at drier sections, to enable access under a safe system of work using a crawl facility under hold to run, while other sections continue to run at production speeds. Splitting of the shaft drive and interlocking of the drier section has been achieved at a mill and this has set the standard. The key issue appears to be that unless the line shaft is split, the existing clutch arrangements, connected to a single drive, present a risk that the machine can be run at other than crawl speed during operator intervention. (Note: there is a possibility of a single mode failure, a clutch failure, which could result in a risk.)
Mills need to explore whether there are other technical solutions that will provide a level of protection equivalent to splitting the line shaft and providing a separate drive. One or two tentative suggestions concerning the number of clutches and other engineering aspects have been made, but these ideas are not fully formed. This needs to be taken forward by those affected with help from the CPI.
Question 13. What are the potential solutions for tail feeding?
Tail feeding is a key issue in achieving compliance with MPS. There is a need to ensure feeding is right first time every time. Where it can be, feeding needs to be reliably automated to eliminate operator intervention and reduce down time. The two tail feeding conferences organised by the CPI will no doubt answer many of the specific queries mills may have. Further information will be circulated after the second conference on the 20 June 2001.
Question 14. Full face guarding or ESPDs at the reel up has been difficult to achieve, what is the view on this?
The configuration of the reel up varies enormously from mill to mill, not least as a consequence of the physical limitations imposed by the building and other equipment. This means that it is difficult to provide more than the generic advice set out in MPS. Several mills have used a combination of ESPDs, fixed guards and interlocked distance guards to achieve the required level of protection.
