Hardware and Pivot Doors

Rob Campion’s post a little while ago on Pivoting Entrance Doors raised some good points on handling pivot doors. In this first post I’d like to go a step further and discuss the pivot hardware side of things.

Our office receives on average 25-40 calls a week requesting information on what hardware to use for pivot doors. These range from interior domestic hollow core doors to one just last month for a 500KG masonry clad behemoth, and just about everything in between. Most common over the last few years has been a large formal entry door in a residential application, so I’ll focus on that.

Having established the door is for residential use there are a number of questions to be asked (indeed these are the same for any application): 

1. Door size, height, width and thickness?
2. Location of pivot point (effective width)?
3. Construction and approximate weight?
4. Single or double action?
5. Locking devices, mechanical, electrical or a combination of both?
6. Sill and transom details
7. Is the door to be self-closing or free swinging?

The door weight for instance is going to determine which model of load bearing pivot or floor spring is appropriate.  The effective width of the door (pivot to leading edge) will greatly influence the strength selection in the case of a floor spring or transom closer.

Self latching/locking devices, especially electrical devices will greatly benefit from a single action configuration and being able to utilize an offset spindle (more on this later).  Sill details often influence the depth of the floor preparation & often require the use of extended spindles to ‘hide’ the floor spring or pivot.

Door construction (typically timber or aluminium joinery) dictates the type of door strap used to connect the door to the pivot

A lot of readers will have experienced this ‘20 questions’ scenario when calling for information. We know it’s a pain, but better we get it right from the beginning, because it can be anything from mildly annoying to catastrophic if things go wrong.

A good general rule is the bigger and heavier the door, the more control and therefore detailing required to get it right.

Okay, so let’s say the door is a 2.6m high, 1.6m wide and 50mm thick zinc clad timber door weighing in around 200kg. The transom will be timber framed and a 20mm rebate is required at the threshold in line with the exterior face of the door. You’ve selected a tile floor you want to run up to the rebate and the pivot point is to be 400mm in from the edge giving an effective width of 1200mm.  The door needs to be self securing and wired to an access control system for security and monitoring purposes.

So first off, we need a BTS80 Floor Spring to cope with the weight (max 300KG). I’d typically go with an EN 4 strength because of the width of the door, strong enough to close it, but not so strong as to be too heavy to open.

Because we will be electrically locking the door I’m going to recommend the door be single action and therefore use a 3 Deg Offset Spindle. These little gems will keep a positive pressure on the door at the closed position by making the floor spring think it always has another 3 degrees to go before reaching 0 degrees. These also help enormously with closing doors against brush seals etc.

To overcome the rebate in the floor a 30mm Extended Spindle is required. This enables the floor spring to be ‘concealed’ under the tile with just the spindle projecting through to engage the Bottom Door Strap. This is where you need to speak to your tiler and make sure the tile covering the floor spring is removable. A common solution is to silicon the tile in place rather than grout so the tile can be cut out later if need be for servicing etc.

The timber construction means we can use the standard 7421 Bottom Door Strap. Were the door any wider I would suggest using a longer custom made version.

In every instance we always recommend using the 2300 Sealing Compound. This is an inert, two pot epoxy sealant that sets to a firm jelly-like consistency. When poured over the floor spring mechanism it greatly inhibits corrosion due to condensation or moisture collecting within the cement box.

To the top of the door now and we need to provide a robust pivoting method that also allows the door to be simply mounted and removed. In this case the 8066 Steel Top Pivot Assembly is the beast of choice. The cantilever arrangement allows the door to be loaded on to the floor spring and then offered up to the top pivot in the open position. The pivot is then engaged into the door portion via the cantilever arm, thus securing the door in place.

These two pivot points MUST be perfectly plumb! I cant stress this enough. All too often the cause of doors binding on the floor is a simple case of either the top pivot not being installed plumb with the bottom pivot, or the top pivot not being securely fastened to the frame. As you can see there is +/- 10mm of adjustment so there’s absolutely no reason for these two points not to be perfectly aligned.

And now that the door is installed, the only thing left to do is adjust the closing speeds to suit the location and clients requirements. Hopefully some one has kept the instruction sheet handy, or just call the DORMA office and we’ll talk you through it.

Easy peasy.

There are any number of variations to this scenario and a whole raft of solutions that may be applied. Subtle differences in products and combinations can afford greatly differing outcomes so I encourage you to post, call or email and discuss your project.