This calculator will help determine whether an outdoor enclosure complies with the Smoke-free (Premises and Enforcement) Regulations 2006, ascertaining whether it is substantially enclosed.

A shelter is substantially enclosed if it has a roof and there is an opening or aggregate area of openings in the walls, which is less than half of the total area of the walls. A roof includes any fixed or moveable structure or device, such as a retractable canvas awning, capable of covering all or part of the shelter.

Any surface area of the walls not open is considered an **enclosed surface area**.

Other structures that serve the purpose of walls and constitute the perimeter of the shelter are included when calculating the **enclosed surface area**. Doors, windows, or other fittings that can be open or shut are also included as **enclosed surface area**.

Enter the length and height of the four walls of the enclosure being assessed. These measurements determine the total surface area of the walls. Press the CALCULATE button to add the total surface area to the results equation in Step 3.

Total Area is: 0

Add any sections of the four walls that are an **enclosed surface area**. You can choose what type of shape each enclosed section is, using the dropdown menu below, which will enable you to add the shape's measurements.

Once you have input the shape's measurements, press the ADD button to deduct that area from the total available surface area from Step 1. Once all enclosed sections have been added, you will be given the final open % area in Step 3.

Select Shape

Here are the results:

Total wall area is: 0

Total enclosed area is: 0

Total available area is: 0

Percentage available open area is: TBC %

*A percentage of 50% or greater is required to comply with the Smoke-free (Premises and Enforcement) Regulations 2006.*