How DVSA requirements shape the dimensions of your Class 7 MOT bay

By Pavan Jheeta

If you’re building a Class 7 MOT bay, it’s easy to focus on the equipment itself.

But the DVSA has specific requirements about the space you need. And that can have a huge impact on the design of your bay — as well as how it fits into the layout of your workshop.

Here are the dimensions you need to know when you’re planning a Class 7 MOT bay:

 

Test bay dimensions

The first step is to make sure you’ve got enough space for the bay as a whole. While Class 7 vehicles are determined by their weight, their sizes can vary — which means the safe working space in your MOT bay can vary, too.

In most cases, you’ll need to find a location for your test bay with:

  • A width of at least 4.2m
  • Headroom of at least 3.2m
  • And an entrance and exit that’s at least 3.2m high and 3.0m wide.

That covers the basics. But it comes with some exceptions:

If the entrance or exit is part of the brake test standing area, the door needs to be at least 3.5m wide (compared to the standard 3.0m).

If your MOT bay uses a vehicle lift, things get a little more complicated. For a bay with a lift, you’ll need:

  • At least 4.8m headroom (measured from the lifting platforms when fully lowered)
  • Headroom that extends 500mm beyond the outer edges of the lifting platforms
  • Headroom that extends 500mm in front of the platforms (the non-drive-on end)
  • Headroom that extends 1000mm to the rear of the platforms (the drive-on end).

These extra specifications might sound complex. But they’re designed to make sure your teams have enough safe working space to inspect vehicles when they’re raised on the lift. (And to account for a wide range of vehicle shapes and sizes.)

 

Inspection pits

If you’re building a test bay that uses a pit, the space and layout becomes even more important — for both the safety of your teams, and compliance with DVSA regulations.

For a Class 7 MOT bay, a vehicle inspection pit needs:

  • A working length of at least 6.0m (uninterrupted)
  • A minimum width of 760mm and not more than 1.3m over the working length measured across both pit walls
  • A depth of at least 1.4m and not more than 1.8m over the working length
  • Access for workers that doesn’t affect the working dimensions (steps may be an exception if there’s a clearance width of at least 600mm).

These strict regulations don’t leave much room for error, especially when we’re talking about the significant groundworks that come with any vehicle pit.

That’s why it’s always important to choose a reliable installer for your inspection pits — one that’s experienced with Class 7 MOT bays, and knows the DVSA requirements inside and out.

 

Headlamp testing

Space and distance are critical to the accuracy of headlamp tests — which means the layout of your Class 7 MOT bay needs to account for it.

The DVSA requires that all headlamp testing installations have:

  • A clearance of 600mm behind the headlamp aim tester optical head
  • A clearance behind the optical head that’s free from floor-mounted equipment
  • A vehicle standing area certified as flat (to within ±6mm in any 3m)
  • A standing area 2.5m wide and 4.5m long (measured from the datum line)

(The datum line is the reference point used for aligning and positioning the vehicle in relation to the headlamp tester.)

 

Brake testing

Compared to the other equipment in a Class 7 MOT bay, your brake testers are usually the most demanding in terms of space — with requirements far beyond what you might expect.

But there are some key differences, depending on the type of brake tester you’re using.

If you’re using a roller brake tester, you’ll need:

  • An unobstructed working area at least 14m long and 3.5m wide
  • A brake tester located centrally in this area
  • At least 600mm clearance between the brake tester and a pit or lift.

With a plate brake tester, you’ll need:

  • A brake tester centrally located in an area at least 3.6m wide
  • A clear area of 7.0m in advance of the tester (this can be partially or fully outside)
  • Any doorways in the advance area to be at least 3.6m wide
  • A clear run-off distance of 4m after the brake tester working surface (excluding any part of the lift platforms)
  • At least 600mm clearance between doorways and ramps (if the plate surface isn’t flush with the floor)
  • A clear distance of 7.0m between the tester and lifts or pits (in the case of a drive-through setup with the plate tester after a lift or pit).

No matter which type of brake tester you’re using, you’ll need to allow plenty of extra space — which means careful consideration and planning when you’re setting up a new MOT bay.

 

Looking to make installation easy?

With so many dimensions and spacings to consider, installing an MOT bay can be a complex process.

(Especially if you’re working with a smaller workshop, where every bit of space matters.)

So if you’re looking to add a new test bay to your premises, the easiest way to get started is by talking to an installer — like the expert teams we have on-hand right here.

You can get the full details of the equipment and processes we include in our Class 7 MOT bay package — or start a chat with an experienced installer to find out how we can help.