The Concrete pumping Code of Practice 2019 was approved by the Minister for Education and Minster for Industrial Relations and commences on 2 December 2019. This supersedes the Concrete pumping Code of Practice 2005.
The updates to the Concrete pumping Code of Practice 2005 ensure that the code:
- is responsive to industry needs and safety concerns
- reflects current best practice in the concrete pumping and construction industry
- is consistent with the model work health and safety laws implemented in Queensland in 2012.
The key changes to the code:
- Clarify that the mobile concrete pump operator is not to carry out the work of a line hand. The line hand is at the end of the concrete delivery hose and cannot monitor the concrete pump operations, including the stability of the concrete pump setup. This change means a minimum of two workers will be required for mobile concrete pumping operations.
- Provide stronger and clearer guidance on maintaining the stability of mobile concrete placing booms and managing the risk of concrete line blockages.
- Clarify that workers other than line hands or concreters are not to be directly under the concrete placing boom during concrete pumping operations. The restriction of workers under the boom, other than the line hand and concreters who may need to work under the boom, reflects the serious safety risks if the boom has a catastrophic failure.
- Update guidelines on working near overhead powerlines.
- Provide stronger and clearer guidance on annual and major (six yearly) inspection requirements. Inspections for concrete pumps and booms should happen daily before commencement of concrete pumping work, weekly, monthly, yearly and with a major inspection every six years.
The Concrete pumping Code of Practice 2019 (PDF, 1.97 MB) will apply to anyone who has a duty of care in relation to the carrying out of construction work involving concrete pumping on or from 2 December 2019.
Stuart Davis from Workplace Health and Safety Queensland presents an overview of the key changes to the Concrete Pumping Code of Practice 2019.
Download a copy of this film (ZIP/MP155MB)
Concrete Pumping Code of Practice 2019 webinar. This is a presentation to give a brief overview of the new Concrete Pumping Code of Practice.
So when was the Code of Practice originally released? In 2005 this occurred. And of course years pass, technologies change, things in the industry change, and also legislation changes. So after a few years we saw that the Code of Practice needed a review, and in June 2015 employer and worker representatives made a joint submission to the then Minister for Industrial Relations requesting a review of construction-related codes of practice, and the Concrete Pumping Code is one of those codes of practice. The proposal was approved and a steering committee was formed.
So who made up that steering committee? Well it's important that you get different opinions from different parts of the industry. It's important to get the views of employer groups, it's important to get the views of worker groups, and of course those people that own concrete pumps and do concrete pumping.
What union was involved? Well the key union involved was the CFMEU, and then of course the employer group was Master Builders Queensland. Then there were a number of concrete pumping organisations and builders on the steering committee. So there was a broad range of groups. So when we look at the Code of Practice, it's not just the view of one group. It's an overall view, and that's reflected in the Code of Practice.
The Concrete Pumping Code of Practice was updated to ensure that it remains responsive to industry needs, it reflects current industry best practice, and is consistent with work health and safety laws. In Queensland in health and safety legislation, there is the Work Health and Safety Act 2011, and then there's the Work Health and Safety Regulation 2011. The Regulation has specific laws and regulations that must be complied with, and then underneath the Regulation there are a number of codes of practice for different sectors of the industry, and in these codes of practice it sets out minimum benchmarks that need to be used.
It's also important to realise that the principles in codes of practice can be used in courts of law for prosecutions under the Work Health and Safety Act 2011.
What are some of the main key changes with the new Code of Practice? As you can see in front of you, there are five key changes. Now I will go through each of these in greater detail during the webinar.
One of the changes that's been made in the Code relates to the number of workers that have to go out with each mobile concrete placing boom. Currently in some situations if the pump was fitted with certain safety features, then the line hand could actually be the pump operator as well. However as time goes on, we've seen that this isn't always the safest option, and there's been a key change made with the Code of Practice. And that key change relates to the number of workers with the pump. There have to be a minimum of two workers with the pump, so the line hand and the operator. The line hand cannot be the same person as the operator.
So why did the steering committee think that this was an important issue, having at least two people per concrete pump? Well if you look at the particular slide of the concrete pump that's gone over on its side, this was an actual situation or an incident in West End in 2017 where the line hand was also the pump operator. The line hand, he was working on the form work down in the excavation, and he was focusing on pouring the concrete. Now what happened was the unit sitting on top, it was sitting on outriggers, and one of these outrigger pads was sitting on a piece of timber that was bridging across the concrete slab to the retaining wall.
Now unknown to the operator, the vibration in the concrete pump caused it to gradually come off its outrigger pad, and then it went over like you can see in the photograph. Now the consequences of this incident could have been very, very serious, because it easily could have resulted in the death of the line hand and the death of workers on the form work. We then realised that it's not just to monitor the hopper. That's not the only responsibility of the concrete pump operator. The concrete pump operator needs to monitor overall safe operation of the unit. Therefore the steering committee decided that it was necessary to have as a minimum two workers operating each mobile concrete placing boom.
What about the concrete pump that you need to select for the particular job? The section in the Code of Practice on this particular topic looks at different issues on site. There needs to be a plan, a discussion between the builder and the concrete pumping organisation, to work out what concrete pump is best for the job. For instance, what volume of concrete do you need supplied? What about the concrete mix design? Is that a specific mix that requires a specific type of pump? What about the delivery height and distance from the pour area? For some jobs, a line pump where the lines go along the ground might be okay, but for other jobs it might be obvious that a boom pump is required. What about site access and condition? Is there room to set up the mobile concrete placing boom? What about cleaning out? Is there room on site to clean out the concrete pump? And there's all sorts of other concrete and construction issues that might be raised that can influence this topic.
What about working under a concrete placing boom? What sort of risks are associated with a concrete placing pump and a boom? Sometimes unfortunately lines can burst, our pipe clamps can become dislodged, there could be a risk to workers around the concrete pump. So the new Code, it specifies that only certain types of workers are allowed to be directly under the boom. And who are those workers? Well the line hand and concreters involved in the deck pour. No other workers are permitted underneath the boom. Now it's directly under the boom.
In addition to this issue, a related topic, the Code of Practice now specifies that you can't have a concrete placing boom directly over site sheds, nor can you have the boom over designated access ways, unless in both of those situations a 10 kPa, or a 10 kilo pascal gantry is provided above either the site sheds or the accessways. Now you might say look, why do we have to do this? This is a big change. Concrete placing booms shouldn't collapse. But unfortunately the reality is that they do collapse. For example, during 2019 we've already had four incidents to date involving concrete placing booms where the booms have collapsed or the outrigger box has failed and the unit has turned over.
Just very briefly, what are these? In January there was a 28 metre mobile unit where the ram on one of the cylinders between the second and third stage failed, and then the boom collapsed to the ground. And then in June there were two other incidents. In one of these, the boom on a 37 metre mobile unit catastrophically failed and then the rest of the boom hit a roof house. And then just recently, a 50 metre unit, the linkage between the second and third stage, failed, and then that boom came down on to the form work deck. And in the other incident, a 28 metre unit, the boom came down. But in that case it wasn't a case of the boom failing. It was the outrigger box failed and then the unit became unstable.
So clearly there is a risk with concrete placing booms, and the new benchmarks on gantries over site sheds and accessways are there for a reason. And also, the restriction on who is under the placing boom is also necessary so as to minimise risk.
Now a related topic has to do with the stability of concrete placing booms. There's a lot of new guidance in the Code of Practice on the stability of this sort of equipment. What are some of those topics that the Code discusses? Well ground factors, the presence of water, the type of ground, whether there's cavities or penetrations, whether there's a crust on the top of the ground, whether the unit is set up next to excavations and trenches. Also there's guidance on timbers, pads and bog mats that go under the outrigger feet. There's also a new formula on calculating the ground pressure so that you can determine the outrigger pad size. And there's also information on short legging of units, the limited situations when you can do this.
As you see in that picture there, the concrete placing unit, it's overturned and the outrigger legs are deep in the ground. That's a particular example of what happens when the pad size isn't big under the outrigger feet. So how can we avoid this? We follow the guidance in the Concrete Pumping Code of Practice. Interestingly, the information in the Code of Practice is now more aligned with the Mobile Crane Code of Practice on ground conditions. For example, the timber size. Now the Code specifies that the minimum size for timbers should be 200mm by 75mm.
Distance from excavations when you're setting up the unit near to an excavation. What are the rules? Well for ground that's non-friable – and by that I mean firm looking ground – the 1:1 rule applies, where the outrigger foot must at least be the same distance away from the excavation as the depth of the excavation. And then for ground which is friable or crumbly, well then you increase the distance to two times the depth of the excavation. There's also a warning in the Code of Practice about crusts on the ground surface, where the surface can seem good, but it's only got a hard crust from the sun.
And then more importantly or most importantly, the calculation for operators to calculate ground pressure. Now in the Code of Practice we have a formula that's quite straightforward. The good thing about most mobile concrete placing booms, most manufacturers now provide a downwards force for the operator to use. Now this might be in kilonewtons or in tonnes. It doesn't matter if it's in either of those units, because you can use the formula that's in the Code of Practice. You can see that formula in the slide, where it's simply to find out the pressure applied by the outrigger you simply have to divide the force, the downwards force, by the area of the pad underneath. And there's different ways of which that formula is expressed. And then we have an example for you to use.
The industry, or rather the manufacturers of concrete placing equipment, have identified this issue for a number of years, and some of the manufacturers even have information on the outrigger leg that the operator can use. So now the operator has much better tools in the Code so that they can work out whether it's safe to set the unit up or not. And plus in the Code of Practice, there's some typical bearing capacities for different ground conditions, whether they be hard rock or going right down to soft clay. And then the operator can compare the result of their formula to the information in the table.
What about powerlines? The Code of Practice now provides more guidance on working near overhead powerlines, and these include planning, exclusion zones, and the role of a safety observer or a spotter. But one of the important changes in the Code is that concrete placing booms should not be operated over the top of energised powerlines. And why not? Well because of the shape and the height of the boom, it doesn't allow for a large separation distance between the powerlines, and the boom movement can be quite rapid. And also there is a difficulty for spotters observing the clearance to get this right.
What about concrete line blockages? Blockages in concrete pumping lines can be a complex issue in itself. There's a whole range of reasons why blockages occur. Some of them are mentioned in the Code of Practice and they're mentioned in the slide in front of you. They could be mix design deficiencies, foreign matter in the concrete, a whole range of different issues.
What about ways to avoid blockages? There again there's a number of ways listed in the Code of Practice. Of course one rule doesn't apply to every type of blockage. Some of those things that are listed there are the need to clean out hoses and pipelines regularly, using a pump with adequate pressure for the line length and the concrete characteristics, minimising the number of bends and short bends. And there's other topics mentioned there.
How about clearing blockages? One of the most important things to note with blockages is that all unnecessary persons needed to be excluded from the pipeline area because of the risk. Now after locating a blockage, ensure that the line is no longer under pressure before attempting to clear it. Perhaps the pump needs to be reversed to reduce the pressure. But of course this is a job for an experienced pump operator who's had a lot of experience with how to clear blockages in the past. Because if you don't do it the right way, well then you can get drastic consequences.
What about traffic control? The Code of Practice includes traffic control procedures that need to be applied. It's particularly important that these procedures are developed when there's more than one concrete delivery truck backing up to the concrete pump. This reminds me of a fatal incident about 15 years ago where a worker was killed. In this particular situation it was a dual feed for the concrete pump. In other words there were two concrete delivery trucks that needed to back up to the concrete pump, back to the hopper. So why was the worker behind the trucks when they were backing up? Well he thought to save time he'd go down to the truck, and as the truck was reversing up the hill, he would move the delivery chute on the back of one of the trucks. Now as he was doing this, he slipped over and one of the trucks unfortunately backed over him and killed him. A very tragic situation.
The information in the Code of Practice gave us guidance on how to try and avoid these types of incidents. And you can see that there's a variety of information that's provided there. Traffic control measures that may be considered include road closures, footpath closures, detours, signing and traffic controllers. And of course for this activity, a Safe Work Method Statement needs to be prepared.
A new section in the Code or Practice relates to movement of delivery hoses for line pumps. Why was this new topic included? Well it's to deal with manual handling issues. So what are the new benchmarks for handling concrete lines on the ground? Well for pipe where the pipe diameter is three inches or more, there needs to be one line hand for every ten metres of workable hose. And when the pipe diameter is three inches or less, there needs to be one line hand for every 20 metres of workable hose. But keep in mind this is for workable hose that's actually physically being moved. It's not for the total length of hose from the pump to the concrete pour area.
There is comprehensive information in the revised Code of Practice on inspection requirements for concrete pumping equipment. There's more detailed information on annual and major inspections. So what are the different types of inspections that are required on concrete pumping equipment? Well there's the daily inspection before the commencement of pumping concrete, there's the weekly checklist or the inspection, there's a monthly inspection, an annual inspection every 12 months, and a major inspection at intervals not exceeding six years.
Now the six year major inspection, some may say why have we maintained this in Queensland? Well because it's probably the most reasonable and the fairest system that we can have. Some may say why don't you base it on volume of concrete that's actually been pumped? Well because volume of concrete pumped, that relies on the good nature of most concrete pumping companies. Whereas most people in the industry will be honest, there will be a minority of unscrupulous ones that might falsify hour metres on the pump.
In addition, what about trucks that drive over rough roads? Simply basing a major inspection on the amount of concrete that the unit's pumped mightn't detect particular faults that have been caused to the pump. Also there could be other issues like storing the pump outside so that there's corrosion. Unlike places like Germany, in Australia we don't have a highly regulated system for competent persons inspecting booms. So you can't use the German model in Australia. And the reality is that catastrophic failures of concrete placing booms are still occurring. As I mentioned before, we've already had four this year.
Of all construction plant, concrete placing booms are exposed to some of the most severe loading. Unlike a crane, a concrete placing boom is exposed to cyclic loading or more regular cyclic loading than a crane. And dismantling the plant is still the best method to inspect those areas of the unit that are hidden during the annual inspection.
You'll see a series of photographs in this particular presentation. In that first presentation, the outrigger box on a mobile concrete placing boom has failed. You can see where it's cracked.
In a close up view you can see where the pencil is placed. Now on that particular unit, it was rusty up to where that pencil is, and then above that, that was a brittle failure. What does this mean? Well these are particular things that should be picked up during the inspection. Now certain things may not be clearly identifiable unless you have a closer inspection or you remove particular parts of the unit. And in some cases you'll need to remove paint so that you can see if cracks exist. Now the other photograph in that slide shows where a box has failed and the crack has been cut out of that particular end of that boom.
This next boom failure, this occurred at Miles in 2011. Now in this particular case, fortunately the line hand was able to get out of the way, and this happened at the start of the job. As you can see from that photograph, the boom has snapped, or catastrophically failed, and the rest of the boom's fallen to the ground. As you can see, a close up in these next photographs. The photograph on the right shows what's called a wear plate under the boom, and this prevents damage to the boom when the boom's folded up. And underneath that wear plate, if you see in the photograph on the left, you'll see where a crack's gone right through the boom. Now this is one spot where that crack would have been hidden from view. So nobody could see this. So if you looked for this visually, you wouldn't have been able to see this. But the photograph on the right actually shows some tell tale rust marks between the wear plate and the boom. This is an indication that there would have been problems in that.
So with this particular incident, if this wear plate had been removed and the boom had been closely examined, then this incident could have been avoided. This is typically one of the issues that should be picked up during the six year major inspection.
The six year major inspection. What does the major inspection need to include? Well in a nutshell, the major inspection is to look at all of those parts of the placing boom that you can't look at during the annual inspection, all of the critical parts where a crack could be hidden or you might have rust that you can't see. And that's why you need to pull the unit apart. It's a comprehensive inspection that needs to be overseen by a registered professional engineer of Queensland. Where the manufacturer provides instructions and tolerances on parts, these need to be followed. So there needs to be tolerance checking or replacement of all critical bolts and pins. Of course it has to include the outriggers and feet.
Where a part's been replaced within two years, the engineer may decide not to dismantle in that area, and non-destructive testing should be carried out by an independent testing authority.
But it's not much use having a comprehensive major inspection done unless you can prove what's been done. So with the major inspection, a pump owner needs to get a detailed report. What are some of the things that you need in that report? A summary of the history of the unit, a manufacturer's major inspection criteria, where that might exist, extracts from the manual, list of work carried out on the boom, the names of persons involved, signed statements from people who have done work on particular components on the unit. So in a nutshell, it's got to be a detailed report for the unit.
But you might say 'My pump's done very, very little use. Why do I have to pull it apart?' Well there might be situations in which you can verify that your unit has very little work. In this case, it can't just be based on the owner saying that the unit hasn't done much work. There has to be a comprehensive written document that explains why a strip down or dismantling of the unit isn't necessary. And this might include tolerance checking of accessible components, a detailed knowledge of the specific make and model so that the engineer knows that these units don't have a history of failure, and a list of work that's been carried out on the boom. But I just need to stress that this is really the exception rather than the rule.
When does the Concrete Pumping Code of Practice commence? It commences on 2nd of December 2019. What do you need to do if you're involved in the concrete pumping industry? You need to become familiar with the Code, have a good read of it, make sure that you understand it.
So thanks for you time in looking at this webinar. And if you want any more information, go to our website.
[Closing visual of slide text saying 'Questions and contact details', 'Further information on the Concrete Pumping Code of Practice 2019 (including a comparison table) can be found at this website', 'https://www.worksafe.qld.gov.au'']
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