Like many folks, of many different communities, I’ve moved my group-based activities online. As education went digital, so did religion. So, with countries looking at how get out of lockdown, groups are thinking about how to get back together for communal activities, while keeping to the governments guidelines. There was a call this morning from my community for someone who could work out how many people we could get in the building. There may be lots of communities (faith, educational, community or voluntry) that have someone who can calculate this value, but if you don’t here’s how to do it. (I’ve also written ‘google sheets’ which will do the calculations for you if you want: the links are at the bottom of this page.)
Step 1: Measure
You need the length and width of the space in which people normally stand. Most places of community worship or prayer have a regular shape (a square or rectangle), so you need to measure the two sides of the rectangle. I’ve suggested two different ways of getting these figure: the best way of doing this is a with measuring tape (or a surveyers reel/tape if you’ve got one); the second option, if you can’t get access to your building, is to try using google maps to get a rough estimate.
The second option is a bit of a hassle because you need to remember how much of your buildings ‘footprint’ (as seen from the air!) is normally used for people to sit or stand in, but there’s two examples of buildings I’ve done the calculations for below.
You need to find your building on google maps and zoom in until the outline of your building fills the browser window/display. Take a ruler and measure on screen the three values in centimetres (don’t zoom in or out while you do this, make all three measurements at the same time): the length of the ‘scale’ bar on the bottom right hand side, and the length and width of the space people normally stand or sit. You also need the number to the left of the scale bar.
In the first example below the alter and choir stalls are in the top 1/3rd of the buildings floor space, so the length is measured at 6.0 cm and the width as 12.2 cm. The scale length is 1.1 cm and that represents 2 metres.
First of all you need to divide the scale by it’s length, so that’s 2 m/1.1 cm in this example, which gives us 1.81 (m/cm). We multiple the 6.0 cm and 12.2 cm by 1.81, giving us a length of 10.9 metres and width of 22.2 metres.
In the second example below the altar is in the west end of the building and the first few metres are a reception space, so the length is measured at 9.0 cm and the width as 3.0 cm. The scale length is 1.4 cm and that represents 5 metres.
Again we, divide the scale by it’s length, so that 5 m/1.4 cm in example 2, which gives us 3.57 (m/cm). We multiple the 3.3 cm and 9.0 cm by 3.57, giving us a width of 11.8 metres and length of 32.1 metres.
Step 2: Calculate
Now that you have measured the width and length of your seating space, divide each number by 2, round down both numbers, add one to each and then multiply them both together.
That’s a bit of a handful, so let’s break it down with our examples.
For Example Building 1, we had a length of 10.9 metres and width of 22.2 metres. So for the length:
10.9 metres divided by 2 becomes 5.45
5.45 rounded down becomes 5
5 add one becomes 6
For the width:
22.2 metres divided by 2 becomes 11.1
11.1 rounded down becomes 11
11 add one becomes 12.
So Example Building 1 has a space where people can stand 2 metres apart in 6 rows and 12 columns. This gives a total of 72 people (6 x 12).
For building 2, we had a a width of 11.8 metres and length of 32.1 metres. So for the length:
32.1 metres divided by 2 becomes 16.05
16.05 rounded down becomes 16
16 add one becomes 17
For the width:
11.8 metres divided by 2 becomes 5.9
5.9 rounded down becomes 5
5 add one becomes 6.
So Example Building 2 has a space where people can stand 2 metres apart in 17 rows and 6 columns. This gives a total of 102 people (17 x 6).
Step 3: What about pews?
Many traditional churches still have fixed pews, and pews are tricker because people are forced to sit in fixed spaces (and you won’t be able to get the measurements from Google maps). The three things to know is how far apart your pews are, and how long they are, and how many you have. How many pews you can use depends on how far apart they are. Look at the table below.
|Distance between pews||Pews used
|2 metres or more||Use every pew|
|Between 1 and 2 metres||Use every second pew|
|Between 66cm and 1 metre||Use every third pew|
|Between 50 and 66 cm||Use every forth pew|
This gives you the number of pews you can use. The number of people that can be fitted into a pew is calculated in the same way as the ‘width’ in step 2.
As an example, a church as 17 pews arranged as a centre block (which is 9.2 metres wide) and two side blocks (each 4.7 metres wide). The pews are 86 cm apart.
We need to use every third row, shown as the red pews in the diagram below, so we can use 6 pews.
The number of people that can be fitted in each pew is calculated as follows:
For the 9 metre central block,
9.2 metres divided by 2 becomes 4.6
4.6 rounded down becomes 4
4 add one becomes 5
So the central block has 30 (5 seats per pew and 6 pews) available spaces.
For the each of the two side blocks,
4.7 metres divided by 2 becomes 2.35
2.35 rounded down becomes 2
2 add one becomes 3
So each side block has 18 (3 seats per pew and 6 pews) available spaces.
The total available space is 30 + 18 + 18 = 66 spaces.
Step 4: Consider diagonal patterns.
If your stuck for space after doing these calucluations, you might want to consider staggering the seating, like in the diagram below.
This works well if your width measurement (in metres) rounds down to an odd number, or if your pew distance falls into the red measurements in the table below:
|Distance between pews||Pews and seating
|2 metres or more||Use every pew, any arrangement|
|Between 1.7 and 2 metres||Use every pew, with staggered seating|
|Between 1 and 1.7 metres||Use every second pew, any arrangement|
|Between 85 cm and 1m||Use every second pew, with staggered seating|
|Between 66 and 85 cm||Use every third pew, any arrangement|
|Between 66 and 57 cm||Use every third pew, with staggering|
|Between 57 and 50 cm||Use every forth pew, any arrangement|
In the example above the distance between the pews was 86 cm, so we might be able to get more people in if we stagger the seating arrangements.
The pews were 86 cm apart, so if we adopted a staggered seating arrangement we need to use every second pew. (See the diagram below.) So starting with the central block, we now have 8 pews available. Each of the pews will seat 5 people (the same as the calculation above). So we can now fit 40 people into the central block.
When we look at the side blocks, we can still use every second pew. However the pews are only 4.7 metres wide. In the calculation above we worked out that 4.7 metres could take 3 people per pew. However, because 4.7 m rounds down to an even number, this means that every second pew we only have 2 seats (because the third person would be sitting in the aisle!). So for each side block we have four pews with 3 seats, and 4 pews with 2 seats, giving 20 seats, just two more than the ‘non-staggered arrangement’.
The total number of seats available in this space using the straight line arrangement was 66, the total number of seats available using the staggered arrangment is 80.
Step 5: People ‘flow’
It’s worth remembering that if you have doors that people need to go in and out while others are in the space, then available seats will need to be 2 metres away from the door.
If you have pews with someone stilling in the middle of a pew, then they may need to walk past where someone else has been sitting. While they might be 2 metres away from that person, if they both touch the same spot of the back of the pew in front, that could lead to formite spread.
Families may want to sit together in a group. So if a family group takes up 2 metres of pew space, theres not going to be a two metre gap to the next person any more.
Mr Ben has put together an online calculator to help people with these calculations. The link is here.
If you want a closer look at some of the calculations there are four different google sheets to help with the calculations are linked in the table below. Unfortunately, you need a google account to access them. Excel versions are linked below as well: but unfortunately you then need Excel to open them! In each case the white boxes are where you put your numbers and the final seat numbers are in red font.
|Spreadsheet name||What it calculates||Google sheets link||Excel download|
|Seating numbers from Gmaps||Will calculate the number of space you have in an aligned pattern based on measurements from Google maps. This spreadsheet doesn’t calculate staggered patterns.||Link||Seating numbers from Gmaps|
|Seating numbers||Will calculate the number of spaces you have from direct distance measurements (using a measurign tape) for both aligned and staggered patterns.||Link||Seating numbers|
|Pew seating -aligned||Will calculate the number of spaces you have from the width, number and spacing distance of pews, using aligned/grid patterns only.||Link||Pew seating-aligned|
|Pew seating – staggered||Will calculate the number of spaces you have from the width, number and spacing distance of pews, using staggered only.||Link||Pew seating-staggered|
The comments are active on this post, so if you want to talk about your setup, or the calculations, or some improvements to the blogpost or the calculation, use the comments option.
We’ve done my best to try and represent the geometry, and assign the calculations, online calculator and various spreadsheets as accurately as we can, but each space set up is different so the final decisions are your’s (and your organisation’s).
Postscript thoughts (26th May 2020)
There has been some discussion on my facebook about how much complexity family groups would add, how we get people to stay in same one place for any period of time, and how to dictate the ‘flow of people’ to maintain social distancing. These are all valid points to address, and would need creative, individual solutions for each community and building. I do think that having a value for the number of people that can fit in a space is an important starting point.
One issue that has come up is how you calculate the numbers if ‘desks’ rather than people have to be two metres apart, or if everyone has to have a 1 metre diameter bubble before the 2 metre measurement starts. OK, that’s something we can work out.
Let’s use the example of Building 2 above were we had a width of 11.8 metres and length of 32.1 metres. When we do the division part of the calculation, we need to do so by 3 (which is made up of the 2 metre social distancing and the 1 metre bubble). So for the length:
32.1 metres divided by 3 becomes 10.7
10.7 rounded down becomes 10
10 add one becomes 11
For the width:
11.8 metres divided by 3 becomes 3.9
3.9 rounded down becomes 3
4 add one becomes 4.
So Example Building 2 has a space where people can stand in 1 metre bubbles with these bubbles being 2 metres apart in 11 rows and 4 columns. This gives a total of 44 people (significantly lower than the original 102).
If you wanted to stagger the rows, then the distance between rows is reduced, and is calculated by the following equation:
The distance between rows = (Social distance + bubble) x 0.87
It’s been pointed out that a simpler calculation is to measure the length and width of the room in metres, multiply both together to get the area, and divide by 4 to get the allowable number of people. This is a good approximation, but differs from the calculations in this blogpost in two ways: firstly, the ‘divide by 4’ doesn’t account for distances that are ‘odd numbers’ (so for example, a room 11 m x 4 m (44 m2) doesn’t have eleven ‘2mx2m squares’ in it, it has ten 2mx2m squares’ and two ‘1mx2m squares’ in it); secondly, these calculations allow people to stand against walls, where as the ‘divide by 4’ means that fewer people stand 1 metre away from the walls (for example a 10 metre line will allow six people to stand on it 2 metres apart, if two people stand at the very ends, whereas if the people at the end stand 1 metre from the end, it can only fit five).