Tipping force and Center of gravity for wall fitted furniture

In summary, the manufacturer recommends using metal L brackets to affix the unit to the wall and spacing ribs on the back to make it difficult/impossible to tie the back of the unit to the wall studs. The calculations were done correctly but convincing the client to have a deeper plinth may be difficult.
  • #1
tivva
5
0
Hi All

I was wondering if anyone can assist with a task of calculating whether an MDF unit will tip over if fixed only to the wall behind it with mechanical fixings as shown below. And what force will be required to do so. I've given it a try. Let me know your thoughts, would be much appreciated. Thanks!

 
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  • #2
Welcome to PF.

What does the manufacturer recommend for affixing that unit to the wall? What is the spacing of your wall studs?

tivva said:
whether an MDF unit will tip over if fixed only to the wall behind it with mechanical fixings as shown below.
And why do you say "if fixed only to the wall"? Is there an option to install legs under the front edge to add strength? Is there a maximum load specified in the manufacturer's documentation?
 
  • #3
We are the manufacturer and we are advising the designer in this case. Wall studs are 600mm apart.

There is an option to extend the plinth and make it deeper but we need to prove to the designer that it is necessary.
 
  • #4
Sorry, what is a plinth?

Also, looking at the mechanical drawing, it looks like there are spacing ribs along the back of the unit? That will hold it away from the wall and make it difficult/impossible to tie the back of the unit to the wall studs. I've hung a fair number of cabinets, and that's how you make the mounting strong -- deep screws through the back of the cabinets into the wall studs (and lots of them)...
 
  • #5
berkeman said:
Sorry, what is a plinth?

Also, looking at the mechanical drawing, it looks like there are spacing ribs along the back of the unit? That will hold it away from the wall and make it difficult/impossible to tie the back of the unit to the wall studs. I've hung a fair number of cabinets, and that's how you make the mounting strong -- deep screws through the back of the cabinets into the wall studs (and lots of them)...
They will be using metal L brackets. 50mm angle shoulder and 150mm tall with 6 screws in each. They tie the “offset” ribs woth the brackets, then screw the back panels to them.

My main question is though are my calculations correct? And how to convince client to have a deeper plinth.

Plinth is the box that the drawer carabiners sit on.
 
  • #6
I’ve done all my calculations based on this video:



There is part 1 and part 2 as well.

However, my center of gravity is past the tipping point which makes me think that perhaps I should put in the distance to it with a minus and the result will be not 95kg but -95kg…
 
  • #7
tivva said:
They will be using metal L brackets. 50mm angle shoulder and 150mm tall with 6 screws in each. They tie the “offset” ribs woth the brackets, then screw the back panels to them.
Sorry, I still don't understand. What is the purpose of the ribs in the back? They can't be seen from the front, so they can't be a cosmetic feature. And they eliminate the possibility of using traditional mounting practices like is done all the time for cabinets, bookshelves, etc.

And is adding a few legs to the front side a possibility to add even more strength?
 
  • #8
Furniture calculations are very difficult for several reasons:

1) The real load is not the weight of the furniture plus the weight of the drawer contents, but all of that plus the force from the heavy person that stumbles against the fully loaded open drawer.

2) There are multiple points of failure. The unit itself can break. The brackets can fail. The screws can pull out of the wall. The wall can fail. The weakest of those points will be what fails. This requires more than just one calculation.

3) You cannot control the workmanship of the installation. The instructions can specify screw size, screw length, and fastening into wall studs. The installer can drill the wrong size pilot hole, miss the stud entirely, fasten into the very edge of the stud, get less penetration because of thick drywall, and find other ways to get a substandard installation.

4) We have a communication problem here. We know how to calculate, but we need to start with a better defined problem. For example, it is difficult for us to explain exactly why the exact location of the mounting screws is important.

This is a case where a good test is better than any calculation. A good test would be to build a unit, install it, fully load the drawers with heavy stuff, open the drawers, then have a 100 kg (or heavier) person sit on the drawer. Make a video of the test and show it to anybody who questions the design or installation instructions.
 
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  • #9
jrmichler said:
This is a case where a good test is better than any calculation. A good test would be to build a unit, install it, fully load the drawers with heavy stuff, open the drawers, then have a 100 kg (or heavier) person sit on the drawer.
Make whoever does the calculation and says it is safe be the seated part of the first trial.

Nothing like "having skin in the game" to get excellent results! :doh:

Cheers,
Tom
 
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FAQ: Tipping force and Center of gravity for wall fitted furniture

1. What is a tipping force and how does it affect wall fitted furniture?

A tipping force is a force that causes an object to rotate or tip over. In the case of wall fitted furniture, the tipping force is the force that can cause the furniture to fall off the wall. This force is affected by the weight of the furniture, its center of gravity, and any external forces acting on it.

2. How is the center of gravity determined for wall fitted furniture?

The center of gravity for wall fitted furniture is the point where the weight of the furniture is evenly distributed. It can be determined by finding the balance point of the furniture or by using mathematical calculations based on the weight and distribution of the furniture.

3. Why is it important to consider the tipping force and center of gravity for wall fitted furniture?

Considering the tipping force and center of gravity is important because it ensures the stability and safety of the furniture. If the center of gravity is not properly positioned, it can cause the furniture to tip over, potentially causing damage or injury.

4. How can the tipping force and center of gravity be adjusted for wall fitted furniture?

The tipping force and center of gravity can be adjusted by redistributing the weight of the furniture, such as by adding or removing objects, or by changing the position of the furniture on the wall. It is important to ensure that the center of gravity is located towards the base of the furniture for stability.

5. Are there any specific guidelines for determining the tipping force and center of gravity for wall fitted furniture?

Yes, there are guidelines that can be followed to determine the tipping force and center of gravity for wall fitted furniture. These guidelines take into account factors such as the weight and dimensions of the furniture, the type of wall it will be attached to, and any external forces that may act on the furniture. It is important to follow these guidelines to ensure the safety and stability of the furniture.

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