We all put off things we’re not too keen on doing, cleaning out water troughs, trips to the dentist, decorating the kitchen…. there can be quite a list. One of the reasons we put off stuff is the associated paperwork, rule following and bureaucracy.  That might be something that’s putting you off changing the silage storage on your farm because there are lots of rules - oh that and the cost..! Most of the rules are there to make sure the silage stored in a clamp doesn’t cause pollution and that’s a good thing, but the way the rules are written make it intimidating to many. If you can see past this, or get someone to see past it for you, in essence the rules are there to make sure someone has thought about the clamps and designed a compliant structure.

Who can actually design a new silage clamp?

We are currently in the (fortunate?) position where a farmer in the UK can still design a silage clamp themselves and perhaps even build it themselves too. In a world of ever more rules and regulations we can’t be sure how long this will last but it still holds true at the end of 2023. But design is a very loose and diverse term - layout design - detailed design - structural design are some of the areas you might consider. In essence you could think off these as follows:

• Layout design - where you’re going to build the clamps and what size and shape.

• Detailed design - falls on the floor, drains, effluent tank size etc

• Structural design -  how it stands up and stays where you built it.

Now you might be happy taking on one or two of these design roles, but all three? In most cases people have a fair idea of what they want from the layout and a pretty strong opinion on the detailed design. There are also plenty of confident people who are sure they can build a clamp that stands up too, but plenty more who would like a bit of hand holding over the structural side. Now whilst you can do all of this yourself, I’m going to explain when and why you might benefit from (or need) a little bit of help.

The right layout and location for a silage clamp

This can be the easy bit, often you just know the most sensible place to build a new silage clamp. Many call this common sense but as one clever sage once quoted - “common sense is much less common than you would think”. Well it is with the general public but farmers are a different breed. However there are rules that, however common your senses are, you need to know to make sure you don’t fall foul of the law. The location of the clamp has to be at least 10m from a water course and 50m from a borehole as detailed in the SSAFO regulations. And you really shouldn’t be building the clamps on “made up” ground either so it’s not just common sense.

The clamp layout can have a massive impact on the efficiency too. Poorly designed clamps lead to much, much higher silage losses and this is something you can’t afford in a commercial business.

Getting the detail right for your silage clamp

When you work with something every day of the year you soon get to know what is wrong with the design. The annoying things really make themselves known to you on a wet Sunday morning when everyone else in the world is still in bed. These are the lessons that you, and only you, can really bring to the design party. The detailed design is also about compliance and making sure what you build is within the rules. The actual rules don’t tell you what to build but just what you must achieve. There is plenty of guidance in the CIRIA report to help you build something compliant - if you actually can trawl your way though the report.

Making sure your new silage clamp stands up

The structural design is the most safety critical part of the process, maybe the bit you can’t afford to cut corners on. Now there are plenty of silage clamps that are built by farmers that will stand up forever, but does that make them well designed? I’m not so sure.

Many engineers are (often self) declared as being very good. This generally means that they over design most of their structures. That can make for great, safe silage clamps but it’s not so good for the poor sod paying the bill. A farmer who includes belt, braces and a piece of string in their design, by throwing lots of ready mix at it, is not actually designing an efficient structure. But it’s also not just about how much concrete you put in a foundation, it is all about where you put it, the shape and the reinforcement inside it. Unless the designer understands exactly where the forces are and how to dissipate them into the ground then they are not designing a foundation, but building one and hoping for the best.

Why waste money on a designer?

So you will have deduced that I think you might well be advised to call on the experience of a professional to help you design your new clamp. Well of course I would because that’s what I do, but there is another really important reason why I think this, and it’s all about the money. I was once asked how much it would cost to provide a structural design for a silage clamp foundation and in this case it was £200-£300. The farmer decided this was a waste of money and proceeded without any external assistance. They then purchased about £60,000 worth of materials to form these foundations and set it all up with fingers crossed I assume. To me this was madness because they risked the entire £60,000 (plus labour and plant) to save a couple of hundred pounds. I don’t know if it’s still standing!

And it’s not just the structural side of things. There are also hundreds of thousands of pounds spent on clamps that waste 15-20% of the silage that goes into them because they are badly designed. In a 5000t clamp that’s around £30,000 per year - every year! So yes I’m biased but I am still convinced getting a bit of advice before you commit to spending tens of thousands of pounds is a good idea.

Who should be involved in the clamp design?

So this might be quite a list, although the same person might be doing many of these roles. First and foremost, the poor soul paying the bill should be instrumental in any design process because it’s a business investment not the Taj Mahal. Next the herd manager and/or nutritionist because the silage clamps are there to feed to cows (or the AD plant). Next a skilled professional who is fully across the regulations and a qualified and insured engineer are also key. And finally, perhaps the guys who fill the thing, either the contractor or the farm silage team. Now that’s probably too many to have in a single meeting but it’s important to let these different people have their say about the design of the clamp. Maybe then you can get a compliant, affordable, workable design for your next silage clamp.

If you want to discuss how and who can design your next clamp or any other topics covered in this series, then please contact me at jeremy@silageconsultant.co.uk