Wednesday, April 16, 2014

Science of the Clothesline: Drying optimisation, peg-mark reduction and time/space efficiency


** Warning ** I’m about to spend quite a long time talking about hanging washing on a clothesline. Bear with me.

When I was younger I read the book Cheaper by the Dozen by Frank and Ernestine Gilbreth. I had a thing about big families, but this family was even more interesting because their parents Frank Bunker Gilbreth Snr and his wife Lillian Gilbreth were some of the earliest experts in scientific management or time and motion studies – essentially how to do things more efficiently.

The Gilbreths applied this to their home life, using all twelve of their kids as guinea pigs for time and motion observations. This applied to chores, homework, dressing and bathing – to maximise what would otherwise be wasted time bathing, the children all listened to gramophone recordings of language lessons, to learn French or Latin while scrubbing their dirty feet.

I later taught a class on organisations, technology and change with a basic overview of some of the earliest organisational studies, including that of the Gilbreths and others working to make workers (labourers and factory workers mostly) work faster. The Gilbreth’s focus was not just on increasing work speed like colleague Frederick Winslow Taylor (Faster! Faster! Faster!), but also on worker welfare by increasing productivity or efficiency by reducing the number of motions or the amount of energy needed to perform a task. They filmed workers and analysed posture as well as the number and nature of motions. This video is one of their films with the recommendations included.

As a new mum, a lot of these ideas kept coming back to me. How do I maximise productivity with the least amount of energy expenditure – because, essentially, I was buggered simply from looking after the baby. Every other household chore on top of that was a weight around my neck.

Hanging out the washing feels like an exception to me, though. It’s one of the ones I like. I am not at all a fan of folding and putting away the clothes afterwards, but some days the only time I went outside and took time to breathe was putting the clothes on the line. And while hanging, I pondered the nature of the Gilbreths’ work and how I could apply their methods to this small part of my day. I pondered it a lot. And then I hypothesized, which was really the slippery slope down into this (quasi-scientific) study of hanging clothes. There were no other humans involved in this study so no ethics clearance was sought or granted.  

***

There are a few different issues at play when hanging washing. And like that building trinity (faster, better, cheaper: where you can only ever have two of the three at any one time), there are some overlaps but generally, these issues are antithetical when it comes to how you hang your clothes:

  • Faster drying
  • Space saving
  • Time saving
  • Avoiding peg marks
I should mention that this is an Australian study, so refers to my bloody awesome Hills Hoist (a rotary clothesline) rather than single or parallel lines strung between poles or attached to buildings, etc (although some of these ideas may still apply). Indoor clothes horses or drying racks have their own issues – we use these in winter, but there’s a completely different science at work with indoor drying.

Faster drying

Let’s start with physics, or centrifugal forces, to be exact... or not... seeing as it’s not a real force at all but the inertia of motion (Lovely Husband is muttering that I mean centripetal forces but that’s not quite what I’m after and bugger it, the formula is the same for both: Fc = mv2/r, if you’re interested, and cause I wanted to show I did some research). What is boils down to is rotary clotheslines are flipping awesome because they spin. Not only do they offer the opportunity for general wind effects (as on other lines) but they also allow centrifugal (not real) forces to act on the washing.

In terms of our issue here (faster drying), what is important is that the drying effect is greater/faster the further the object is placed from the central tether. In essence, if there is any line movement at all, stuff hung on the furthest lines from the centre will be dry faster than equal stuff hung closer to the centre. Combine this centrifugal force with the fact that items hung on the outer line have a greater exposure to sun (less chance of  shadow from other items) and you’re laughing.

Where: If you have a single load and a hint of breeze – hang it all on the outer lines; if you have multiple loads, hang bulkier items on the outer lines and smaller, lighter items on the inner ones.

Using our basic formula for line placement (that Greater Movement = Faster Drying Time or GM=FDT), we can then extrapolate optimal peg/item configurations to achieve faster drying times. Given pegs limit movement, greater distance from the peg would allow greater movement. If both of these things are true, then distancing dense, bulky or layered fabrics from the peg would ensure faster drying time overall. On trousers, for example, the layered fabric of the waistband and pockets dries more slowly than other areas. It follows then that pegging trousers by the hems of the trouser legs (with a minimal fold over the line) would allow greater movement of the thickest areas, and thereby ensure faster drying time for the garment overall.

How: Keep pegs away from the thickest folds, layers or parts of the garment. Peg to allow these areas greater movement

Other examples:
  • T-shirts, jumpers and hoodies – peg at the hemline to allow greater movement around the armpits, shoulders and collar
  • Undies - peg at the hip to allow greater air flow through the gusset/crotch and the waistband
  • Socks – variable depending on thickness/type of sock; I use Bonds Cushion Feet which have thicker fabric around the foot, so are hung by one side of the top – this leaves the sock ‘open’ to more airflow

 Space saving

Ever played Tetris? Sometimes hanging multiple loads of washing on a single rotary line feels a lot like that. Ideally, you would have an awesomely windy and scorchingly hot day that'd allow you dry a single load of washing before the next had finished its cycle. But unless it’s February or you live some place like Marble Bar in WA, chances are you’re going to have to shuffle, rearrange or think ahead.

Some items (but not all) lend themselves to being folded or otherwise manipulated in order to minimise their hanging size. Thin and flat items like hankies, tea-towels or bed sheets, for example, can be folded by length or width and then pegged for drying. Other thin items such as business trousers or cotton pants can be folded in half, reducing their hanging space to a single leg-width. Problematic here is that folded items may require refolding in order to expose and dry the inner fabric areas and avoid longer drying times.

An alternative strategy is to make creative use of space, rejecting standard procedure to hang items along the length of a single line. Hanging single items across parallel lines, for instance, dramatically increases the number of items that can be hung in that same space. Even allowing for a slightly smaller inner line, engaging parallel lines permits me to hang up to twenty adult sized t-shirts and shirts with a 10cm gap, compared to 8.5 similar items hanging along the length of the same two lines. This method does increase peg-mark visibility owing to a slight twist in the fabric as you peg to a line running perpendicular to the garment.

How: minimise hanging size or choose alternate hanging methods

Other examples:
  • Business/school shirts/t-shirts – can be hung on coat hangers and placed on the line to dry as they would be placed on a wardrobe rack (pegs placed between hangers can prevent them from sliding and bunching together). This method can help reduce the need for ironing
  • Trousers/jeans – can be hung on clip hangers by the waistband or by the hems of the legs (any trousers that require crisp pleats can be hung using this method to avoid ironing them in)
  •  Underwear and socks – can be hung on a separate clip rack like this or pegged along a wire coat hanger, both of which can then be hung on the clothesline

Time saving

According to the traditional time and motion studies, minimising the number and length of movements while maximising their efficiency helps to reduce overall time needed to perform a task. In terms of hanging the washing and the time spent actually hanging items (as opposed to time spent drying items), this means considering the placement of the basket of clothes and pegs, manipulation of clothes and pegs as well as sorting subsystems.

As in the Gilbreth’s video of bricklayers, bending to ground level to pick up single items is incredibly inefficient whether you’re hoping to get a brick wall built or clothes hung on a line. Raising the clothes basket on a chair, bench or trolley limits the range of motion necessary to pick up clothes and hence speeds up the process.

Picking up multiple items can also increase speed, depending on individual abilities to manipulate pegs or a pre-distribution of pegs on the line (leaving pegs on a line can speed up the process of hanging if they are distributed at appropriate distances along the line for the size of the garment that needs to be hung, effectively eliminating peg gathering from the equation). To reduce peg decay and breakage, I choose to remove pegs from the line and keep them indoors between uses. As such, I acquire both pegs and clothes with each motion. From considered observation, I know I am only able to hold and manipulate a maximum of six wooden pegs at any given time and therefore pick up a number of items requiring said number of pegs. This may be, for example, three t-shirts (3 items x 2 pegs) or six socks or pieces of underwear (6 items x 1 peg). Slinging these items across a shoulder, they are immediately available for hanging rather than requiring additional motions to the basket.

Motion efficiency can also be found in the greater scheme of hanging, utilizing zones and sorting subsystems. As you remove clothes from the washing machine, doing a quick sort of items (putting clothes in a smaller to larger or larger to smaller order into the basket) can assist in maintaining a single direction for hanging starting at either the outer or inner lines (depending on how you have sorted your clothing into the basket). This effectively limits the number of motions needed to reach different parts of the line, if you move the raised clothes basket with each movement to another line (a trolley with wheels will also reduce energy expenditure here).

How: pre-sort items into the basket; raise clothes and peg baskets from ground level; observe personal peg manipulation and adjust number of items accordingly; work in a single direction

Other things to consider:
  • Do you want to sling wet washing across your shoulder? If no, then reduce the number of items to what you can carry in your non-peg hand.
  • Assistants can greatly reduce hanging time by handing you clothes and pegs. This is only a time saving if assistants are well-trained and unlikely to drop clean clothes on the ground.

Avoiding peg marks

Peg marks are a contentious category. Rather than being one of concern over time, space or energy savings, this one’s mostly personal preference or vanity for how one looks or presents to the world. Regardless, I think it’s a category that’s influenced and been handed down to quite a few women.

There are a number of ways to eliminate concern for peg marks entirely: use a tumble dryer, hang clothes on a line without pegs or to stop caring about having peg marks on your clothes. Not all of these are viable options though. In order to reduce marks on clothes hung on a line with pegs, there are two primary strategies: place pegs in places where marks won’t be seen or employ pads or buffers to reduce the pressure of the peg on the garment.

Placing pegs in places where marks won’t be seen is a fine art. It’s an art I learned from my own mother who had a tremendous collection of 80s and 90s business clothes that she didn’t wish to be sullied (and were probably a bit dangerous to put inside a hot tumble dryer). I was taught, for instance, to peg trousers and skirts along the back waistband, t-shirts under the armpits and button-up shirts at the side-seams of the hemline. There are compromises here, though, in terms of drying time given reduced movement of thicker fabrics and increased folds over the line.

An alternative (although one that compromises on hanging time and drying time to a lesser extent) is the use of make-shift pads to act as a buffer between the fabric and the peg. The pad needed really depends on the fabric of the garment but I’ve used dry wash clothes, folded garment bags and even breast pads that have sprung loose from swimmers.

How: place pegs in places where the marks won’t be seen or use make-shift pads to buffer garment fabric.

Other examples:

  • Hanging some garments inside out can reduce visible peg marks
  • Hang shirts, t-shirts or dresses on coat hangers
  • Dresses – hang under the armpits
  • Underpants (?!) or swimmers – by the gusset or crotch
  • Socks and tights – by the toes
Hanging clothes on the line is such a weirdly personal thing. Not only are you hanging up items that touch your skin and the skin of your loved ones, but techniques are generally handed down from parent to child (or parent to adult-child, if they're lazy as). Most of us have pegged automatically and in the same way for years. 

Do you have a strategy for how to hang your clothes? Does it save you time or space, reduce peg marks or help the clothes dry more quickly? Did you learn it from your own mum? 

4 comments :

  1. Centripetal Force:
    http://en.wikipedia.org/wiki/Centripetal_force

    "Centripetal force is generally the cause of circular motion."

    The velocity of the body is the instantaneous tangent to the position on its path of motion. It is this velocity which is constantly changing brought about the force attacting the object to the centre of its path of motion that induces an equal and opposite force, the imaginary, centrifugal force:

    http://en.wikipedia.org/wiki/Reactive_centrifugal_force

    With some co-ordinate transformations and math magic you can treat a rotating frame of reference as a Newtonian intertial frame of reference which means centrifugal forces become "real".

    For a related laugh:

    http://xkcd.com/123/

    ReplyDelete
  2. This was more fascinating than I probably care to admit! But I definitely subscribe to the theory that if something is worth doing it's worth doing well. I'm definitely keen to read Cheaper by the Dozen now. x

    ReplyDelete
    Replies
    1. Fascinating family - the Steve Martin movie of the same name has no likeness to the original story (apart from having quite a lot of kids). One of the things I really liked about it, and later reading I did on the Gilbreths for teaching, was that the wife/mum Lillian was also a professional woman, and generally treated on an equal standing to him in terms of their research. Considering it was the start of the 20th century, it's quite an acheivement.

      Delete

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