Mobile stage merchants will be the first ( and sometimes the second , and third ) to tell you their stages offer significant safety benefits over traditional cable-and-ballast structures . But mobile stage safety isn ’ t in the stages ’ nature so much as it is the product of the relationship between safety theory and safety best practices . Two of the directors of Stageline , one of the most recognizable names in mobile staging , spoke to Event Safety Insights about the relationship between theory and practice in how their company approaches the life and death issue of stage safety .
Mobile Stage Safety ,
In Theory and In Practice
By Jesse B . Staniforth
Mobile stage merchants will be the first ( and sometimes the second , and third ) to tell you their stages offer significant safety benefits over traditional cable-and-ballast structures . But mobile stage safety isn ’ t in the stages ’ nature so much as it is the product of the relationship between safety theory and safety best practices . Two of the directors of Stageline , one of the most recognizable names in mobile staging , spoke to Event Safety Insights about the relationship between theory and practice in how their company approaches the life and death issue of stage safety .
On the subject of the theory of safety , ESI spoke with Stageline ’ s Engineering Director Jonathan Doucet , who has been with the company for more than a decade .
EVENT SAFETY INSIGHTS : What are the guiding principles of safety for mobile staging ?
ESI : How do you go about designing a stage that minimizes human involvement ?
JD : You design with the worst-case scenario in mind , for risk management . Think of what it ’ s possible to do , even if it isn ’ t likely . That could be human error , a huge wind , a storm — just think of the worst conditions operating the stage .
ESI : When you ’ ve figured out what your potential risks may be , how do you design a stage that can be ready for them all ?
JD : The main way to do that is by calculating safety factors . This is where our approach doesn ’ t follow the minimum standards , it exceeds it . A safety factor of 1.6 is considered an acceptable minimum , but if you look at the possibility of dynamic loads and the action of rigging — those alone could have an impact of between 1.5 to 1.7 on any structure . So for us , we make all our safety factor a ratio of 2 / 1 for all load cases we consider , because it ’ s simply safer .
Jonathan Doucet : The basic premise is that we include safety in the design from the very first starting point with any new design and we try to minimize the amount of work that will depend on humans , who are unpredictable . Therefore , all of our designs use sequential deployment , which means that if you want to go from A to C , you have to go through B — you can ’ t go directly to C by accident . We try to do that with everything we design .
ESI : You don ’ t set up your stages the way that anchor-ballast stages are set up .
JD : No . We don ’ t use cables that go directly to the ground or ballasts that are required on all standard units , because they ’ re not safe enough . Instead of ballast , we rely on the self-weight of the equipment since it ’ s always the same and it can ’ t be removed , so that cuts out the possibility of having an error in connection with a critical element for any safe operation of a stage : wind resistance .
ESI : What ’ s the advantage to self-weight over ballast ?
JD : With anchors and ballasts , there are many points where mistakes can occur and things can go wrong : cables are like a chain , where you ’ re always subject to the weakest link . The connection between your cables and your ballasts can be weak . There ’ s friction between the ballast and the ground to keep in mind . When you use guy-cables , you have a lot of things to verify . Any one of those things can go wrong . Self-weight is easier : it makes it very hard to forget anything . This goes back to our first point to minimize the human factor in the equation of stage construction . The more we minimize their involvement and streamline the stage to make their job easier , the more we reduce potential for human error .
ESI : That ’ s a significant increase on the published norm .
JD : From our point of view , norms and standards are existent to state the minimal requirements , the entry points , but nothing in these codes prevents you from doing better . Instead , it ’ s worth asking , ‘ Even if the norms say this is acceptable , is this the safest solution we could provide ?’ We don ’ t gamble with safety , so we adapt safety factors to the realities these stages face , rather than designing them to a minimum imposed criterion . From there we can ask ‘ what ’ s the real target we need to hit , rather than the official one ?’ The ANSI E1.21 – 2013 is the guideline we ’ re supposed to follow , but we pride ourselves with doing more than that .
ESI : How so ?
JD : For wind-resistance , they list 40mph with all windwalls . But 60mph wind is quite common and we see it quite often on various event sites across North America , so less than 60mph is not enough for us . If you remove windwalls , they list wind resistance at 67mph , but for us , we go with 90mph . We ’ ve seen over and over again at events that winds from 60 to 80mph really are possible . You have to be safer than the norm if the norm doesn ’ t seem safe enough .
ESI : On the technical level , how do you build safety into the products ?
JD : You need to always keep redundant systems in place for every element that could involve a catastrophic scenario , like wind resistance for example . If a system fails in resisting strong winds for example , there has to be another system in place to resist it . One thing that we do is that we remove the hydraulics from the calculation ,
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