common sizes of things

I have ‘introduced’ this page in a short post entitled the sizes of things from April 12th 2013. I have compiled it as much for my own benefit as anyone else’s because I’m constantly having to remind myself of common measurements! This is what I have been able to piece together so far (12/4/2013) from a number of reliable sources. I’ve done my best to stick to facts and avoid opinion, and where there are variations based on particular practice or differences in stated norms these are indicated. It is a start! .. but there are many more that could be included. I am hoping that the list will develop, and for that I would welcome any suggestions or contributions you’d like to make. If you would like to add information you will need to include your sources so that I can check them.

I’ve written the measurements wherever possible consistently like so .. ‘6ft 9.1in/1,755mm’ .. i.e. in a form which may be fussy, but accurate and readable for all (unless a particular source is being quoted). Imperial (feet and inches) is given first, not only as a courtesy to the US but more importantly because so many ‘standards’ originate from multiples or divisions of the foot.

Human form

Male Height 5ft 9.1in/1,755mm. Shoulder width 1ft 6.3in/465mm. Head width 6.1in/155mm. Head depth 8.7in/221mm. Chest depth 10in/254mm

Female Height 5ft 4in/1,626mm. Shoulder width 1ft 4.1in/409mm. Head width 5.7in/145mm. Head depth 8.1in/206mm. Bust depth 10in/254mm.

These averages are taken from the 2011 Interior Graphic Standards 2nd Student Edition, produced by the American Institute of Architects. Its main reference work Architectural Graphic Standards has been updated yearly since 1932, as a source of regulated (or advised) measurements for architectural features. Although published in the US it is internationally recognised. The first section of Interior Graphic Standards deals with human proportions and the selected measurements quoted are those of the ’50th percentile’, which basically means the average or central tendency of all subjects measured. Percentiles work from the bottom up .. for example, a woman whose height falls within the 50th percentile will be average in the sense that there are as many women taller as there are shorter than her. For a woman in the 1st percentile all other women will be taller, and a woman in the 99th percentile will be tallest of all.

I’m hoping that the US survey reflects a sufficiently multi-racial balance.

Architecture

Steps or stairs

To explain the terminology first: the vertical face of a step and its height are both known as the riser while the horizontal face (which is trodden on) and its forward depth are known as the tread. Stair width therefore refers to the distance side-to-side i.e between handrails, and headroom is the height available or needed overhead. The step nosing is the common forward protrusion at the top of each riser. The pitch of a flight of steps is the overall incline measured as an angle from the floor.

In The Handbook of Set Design Colin Winslow refers to the risers of domestic stairs ranging from 15cm (6in) to 18cm (8in) in height. He also includes drawings comparing the elegant proportions of a flight of steps with 15cm risers/30cm treads to the less elegant 18cm risers/28cm treads. The former is certainly easier to use, while the latter is on option when space needs to be saved. Winslow also refers to the accepted rule that 25cm (9in) is the maximum height for a rostrum before additional steps are needed to step on it.

Interior Graphic Standards (2011) sets out the measurements as follows .. Minimum width (dwellings) 3ft/914mm, public 3ft 8in/1,118mm. Minimum headroom 6ft 8in/2,032mm. Minimum tread (dwellings) 10in/254mm nosing to nosing, public 11in/279mm. Maximum riser (dwellings) 7.75 in/197mm, public minimum 4in/102mm maximum 7in/178mm. Nosing maximum 1.25in/32mm protrusion. IGS also recommends avoiding having fewer than three risers to a flight.

UK building regulations state that for private/domestic stairs the maximum riser should be 220mm and minimum tread 220mm, with a maximum overall pitch of 42degrees. For public stairs the maximum riser should be 150mm and minimum tread 280mm, with a maximum pitch of 33degrees. http://www.stairplan.co.uk/regulations.htm

Rakes or ramps

When I worked as a stage designer I was initially told, and then learned from personal experience, that the maximum manageable stage rake to walk on was 1:8. The way this is expressed signifies that the slope rises 1 unit (whether an inch, a foot or a metre ..it’s the same) for every 8 of the same units along. This is also the easiest and most accurate way to work out/draw up a rake on technical plans i.e. for example measuring 8 units along and then marking one unit up at that point.

Interior Graphic Standards stipulates that the maximum incline for ramps i.e. for wheelchair access etc. is 1:12.

Doors

It is common for exterior doors to be slightly taller, wider and thicker/stronger than interior ones.

When I was designing for the theatre I was encouraged to make all doors generally 2metres high (considered to be slightly more than average) unless something significantly smaller was needed. I assume the thinking behind this was that the extra height would read better from a distance and also allow a little more for ‘actors with hats’. As a width 800mm always seemed in good proportion to this height, while also making internal divisions (when designing door panels) easier to work out.

Interior Graphic Standards lists a range of common door widths as 2ft/610mm, 2ft 4in/711mm, 2ft 6in/762mm, 2ft 8in/813mm and 3ft/914mm. The only two standard heights given for interior doors are 6ft 8in/2,032mm and 7ft/2,133mm. The height of ‘operating hardware’ (i.e. door handles) is given as typically 3ft 2in/965mm centreline above floor level (or ranging between 2ft 10in/864mm and 4ft/1,219mm). Common door thicknesses 1-3/8in/35mm, 1-3/4in/44mm. Elsewhere in the book, dealing with fire control, it states that a door opening should have a clear height of 6ft 8in/2,032mm minimum and 10ft/3,000mm maximum, and a clear width of 4ft/1,219mm maximum.

In the UK according to door manufacturers or reclaimers such as Dorset Doors (site viewed in 2013, but disappeared by 2015), traditional period doors were made to a range of common sizes, the most common interior door ‘standard’ being 2ft 6in/762mm width x 6ft 6in/1,981mm height. DorsetDoors also lists a range of period interior door sizes from 2f/610mm x 6ft/1,829mm ‘understairs door’ to 3ft/914mm x 7ft/2,134mm ‘very large doors in larger properties e.g. hotels’. These are also the dimensions for the larger type of external/front door, while ‘most front doors from the Victorian period through to today’ measure 2ft 8in/813mm x 6ft 8in/2,032mm according to the above source. Also according to the above, whereas period doors were made in proportion (so wider doors increased in height etc.), modern doors are made with a uniform height of 6ft6in/1.981mm regardless of width.

This is supported by UK sites such as thediyworld.co.uk which gives the standard or most common interior door size as 2ft 6in/762mm width x 6ft 6in/1,981mm height and it is clear from their chart that even common doors of 2ft 3in/686mm or 2ft/610mm retain the 6ft 6in height, with 6ft 10in/2083 only occasionally. The usual thickness is given as either 35mm or 40mm. As you can see, if you want an average still used today, you just need to think of comfortable fractions of a foot.

Victorian period 1837-1901 ‘Internal doors are constructed in the traditional frame-and-panel manner. Doors leading to grander principal rooms can be up to 3ins (7.5cm) thick with numerous panels and applied mouldings. Such features not only indicate the room’s importance, but the greater the density of the wood the more effective it was as a protection against eavesdropping servants. Doors to more modest rooms are often framed in wood less than one inch (2.5cm) thick with very thin undecorated panels.’ Stephen Calloway The Elements of Style p236

There are no set regulations for the direction that doors should open, the ‘swing’ in other words, but there are some norms dictated by common sense. For example interior doors most often open ‘into’ the room, because there is usually more space to accommodate this inside the room than in the hallway or corridor one’s coming from. Also when the doorway is positioned at the corner of the room entered the door will usually swing so that it rests against the perpendicular wall, to save space being taken up. For partly the same reasons it makes most sense for exterior doors to open ‘outwards’, and this also means that a strong door would then be very difficult for a burglar to kick in. But often this can’t be followed i.e. in the case of tower block flats accessed by a relatively narrow walkway or corridor.

Windows

Windows vary a great deal more than doors in terms of size and position within the wall. If thumb-rules are needed Interior Graphic Standards includes the following for fire control .. a maximum of 3ft 8inin/1,118mm above floor, a minimum clear opening width of 1ft 8in/508mm and (in the case of an operable sash window) a minimum clear opening height  of 2ft/610mm.

Floorboards

I have trawled the following bits of information from two very useful style books .. Stephen Calloway’s The Elements of Style and Collins Complete Period House by Albert Jackson and David Day.

Tudor and Jacobean (1485-1625) ‘floorboards up to 24ins (60cm) not uncommon’ Calloway.                                                                                                                     Early Georgian 1714-1765  ‘Planks from the early decades are often more than 12ins (30cm) wide: these were left untreated and were regularly scoured with sand. Later boards are narrower (8-10ins/20-25cm) and, in the principal rooms, were stained and polished at the margins to frame a carpet.’ Calloway p.91                                             ‘By the eighteenth century the size of floorboards had become more regular. Boards about 100mm (4in) wide were used in better-quality houses to avoid shrinkage and distortion problems, while houses of lesser quality had boards 200 to 250mm (8 to 10in) wide.’ Jackson&Day p183                                                                                            Early 19th Century 1811-1837 ‘average width in ordinary houses 7-9ins (18-23cm)’ Calloway

Most common widths now are 8in/200mm or 6in/150mm. 6in floorboards can make a small space feel somewhat bigger.

Reclamation firms such as Lawson’s http://www.traditionaltimber.co.uk/ (viewed 2015)are sometimes good sources of information on the types of wood most often used, common widths, layouts and treatments. Lawson’s has particularly good surface photos!

Standard size of a brick

UK length 215mm width 102.5mm height 65mm. 10mm mortar thickness.

Furniture

It is not difficult at all nowadays to get extensive visual reference for any piece of furniture, whatever the style or the period. It is less easy however to find clear and accurate measurements, especially for the details. Antique dealer’s or furniture restorer’s websites provide a great deal of information, but if measurements are given they are often limited to overall height, width and depth i.e. omitting the more significant seat height and depth. It is important to piece together an idea of what passes for ‘usual’, or ‘normal’ or functional with regard to the common types, styles or periods of furniture and here are just a few reliable sources which can help, followed by my own summaries of dimensions based on these sources.

http://collections.vam.ac.uk/ the Victoria and Albert Museum visual database contains over 1 million objects from the collection with an easy search facility (my search for ‘armchair’ yielded over a thousand examples!). Dates and designer/maker (when known) appear immediately with the thumbnails. Photos are clear and professional, usually including a number of views. Measurements often include details such as seat height and depth. There is also thorough information regarding origin, materials used and supportive ‘object history’.

Alvan Crocker Nye was an instructor in furniture design at the Pratt Institute, New York at the turn of the last century. His well-known book (to give it the full title) Furniture Designing and Draughting : Notes on the Elementary Forms, Methods of Construction and Dimensions of Common Articles of Furniture was first published in 1900. Since copyright has expired it is available for free from the Library of Congress Internet Archive http://archive.org/details/furnituredesigni01nyea  Apart from many useful drawings the book includes lists of common dimensions for different types of chair, sofas and tables.

An authentic and reliable gem of the same kind is Charles H Hayward English Period Furniture 1936, though not available so readily online except for excerpts. This beautiful little book contains many measured drawings (some going into great detail, even including handles and hinges). Also general comparisons of leg, seat, back shapes and ornamentation throughout the ages. Hayward was a prolific writer and editor, with more than 30 books on furniture and woodwork to his name. These were much relied upon especially in post-war Britain and are still highly sought after. Any book by Hayward is a valuable source of information. Another book should also be singled out here, Verna Cook Salomonsky Masterpieces of Furniture 1931 (republished by Dover 1953) which presents the detailed measured drawings for selected items of period furniture from the 16th to 19th centuries.

http://www.cawspi.org/Furniture%20Design.pdf (checked 2015) the Illinois Capital Area Woodworkers website is one of many woodworker sites, in the US or the UK, which include helpful lists of standard dimensions for furniture design. This .pdf includes typical adult figure measurements; standard dimensions for different types of tables and desks, chairs, beds, mattresses; also standards for shelves, cabinets and kitchen appliances.

www.ikea.com the IKEA online catalogue is a good source for quick comparisons of simple, functional styles. Clear photos (rarely more than one full view, but often with close-up details) and measurements confined to overall height, width and depth (found in the ‘Product Information’ section for each piece). Another site which is good in a hurry but which also includes ‘repro-traditional’ styles is www.furniture-catalogue.co.uk

Here are the collected dimensions. Where there is a significant ‘norm’ I have listed this first, but then indicated the most common range of variation:

Dining/table chair Common seat height 1ft 6in/457mm (common range 1ft 4in/406mm to 1ft 7in/483mm); armrests (if included) 7in/178mm to 9in/229mm above seat; common depth of seat 1ft 4in/406mm (common range 1ft 3in/381mm to 1ft 6in/457mm); common width of seat (usually tapered) 1ft 3in/381mm at back 1ft 6in/457mm at front; common slant of chairback 5 degrees; common comfortable height range of chairback 1ft/305mm to 1ft 4in/406mm above seat (but varies more according to style i.e. 10in/254mm low back, 2ft/610mm high back). The average overall chair height for this type is 3ft/914mm, the most common range between 2ft 8in/813mm and 3ft 4in/1,016mm.

Armchair i.e. large ‘cushiony’ type. Common seat height 1ft 4in/406mm (most often lower than table chairs, though some styles can reach 1ft 10in/559mm height with cushion); common overall back height range from 32in/813mm (low back style) to 3ft 8in/1,118mm (high back style); common slant of back 10-15 degrees; common overall width range 2ft 4in/711mm to 3ft 4in/1,016mm; common overall depth range (not just depth of seat) 2ft 8in/813mm to 3ft 2in/965mm.

Table Common height for dining/writing 2ft 5in/737mm (common range 1in/25mm either way); common height for workbench 2ft 8in/813mm; common height range for coffee table (usually same height as sofa seat) 1ft 3in/381mm to 1ft 5in/432mm.

Mattresses Single: width 3ft/914mm length 6ft 3in/1,905mm Double: width 4ft 6in/1,372mm length 6ft 3in/1,905mm to 6ft 8in/2,032mm

Paper sizes

An A4 sheet of paper measures 210x297mm. Why these measurements? .. not exactly easy to remember or reproduce! It has nothing to do with inches. Why not 200x300cm? Then ‘A3’ would be 300×400, ‘A2’ 400×600 and ‘A1’ becomes a rounder 600×800 .. surely easier in many respects? The answer is that the A4 sheet is part of a paper-sizing system first developed in Germany in the 1920’s making use of a very special aspect ratio or proportion involving the square root of 2. When a rectangle with the aspect ratio 1: 1.4142.. (i.e. width measurement to length measurement) is cut in half widthways the two halves will have the same aspect ratio, and so on if these halves are also split. Keeping the same page proportion between one size and another has many advantages especially nowadays in terms of scaling content up or down without any wastage (although I fail to see how that could have been quite so attractive in the 1920’s before there were photocopiers etc ?). But from the beginning the attraction, and the reason why is was adopted so rapidly by many countries even before WWII, must have had as much to do with commerce as end-user benefit. The largest sheet size in the DIN (as it was originally termed) hierarchy was A0, designed to be as near as it was possible to get to an area of 1 square metre in the 1:1.4142.. aspect ratio. Paper weight was also defined by the square metre, as it still is. So it made it possible for manufacturers to measure and portion quantities of any paper size within this system more easily and accurately. The sizing system has now been adopted almost worldwide and is known as ISO 216.

Here are the four most useful paper sizes in millimeters A4 210×297 A3 297×420 A2 420×594 A1 594×841 and the chart below displays these in context. The US has it’s own sizes i.e. ‘Letter’ and ‘Legal’ and a comparison is superimposed (courtesy of Wikipedia).