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Tippy-Tap: An Outdoor Hand-washing Device


‘Mukombe’ Tippy-Tap

Every year, 3.5 million children die from diarrhea and acute respiratory infection in developing countries. A simple act of washing hands with soap can prevent these illnesses and save 1.2 million of these children. The solution lies in a simple hands-free device called Tippy-Tap.

Permaculturists and gardeners can use it as a good outdoor hand-washing device, but for thousands of volunteers and NGOs working in developing countries, this could be a very handy and effective device to improve hygiene.


Tippy-Tap

Tippy-Tap is a low cost, low water, low tech device to wash your hands in areas where there is no running water. The first version of Tippy-Tap was made 30 years ago by Dr Jim Watt, a Salvation Army doctor working in Chiweshe, Zimbabwe. He came up with a novel idea of converting the common gourd or calabash into a hand-washing device, which came to be known as ‘Mukombe’.


Naturally occurring mukombe

How it Works

The gourd or calabash, locally called mukombe, can be used as a container. A gourd with a long curving neck is chosen and the end of the neck is sealed off with a wooden plug or cork. A small hole is made in the plug for water to pour out. At the top, a hole is cut to fill the mukombe with water. The whole device is suspended at a special angle by a string passing through two holes at the top of the mukombe (1).


Drawings by Dr. Jim Watt of his mukombe

When a filled mukombe is tipped, water from the reservoir passes up the neck. As the mukombe comes back to its resting position some water is left at the end of the neck. It is this water which drains down through the hole in the plug which is used to wash hands. The flow stops automatically when the small reservoir in the neck runs out (1).

Mass Production

Though Dr. Jim Watt studied the anatomy of gourds and came up with simple easy steps to convert it into a tap, the idea did not spread among common people and went into obscurity. Only recently was this innovation given its due, when the Zimbabwean innovator and scientist Dr. Peter Morgan thought of mass producing them.


Mass produced plastic mukombe

Since the naturally occurring mukombe varied in shape and size and often did not have the ideal shape, Dr. Peter Morgan and his team made many fibre glass replicas to find the ideal shape for optimum performance. At the end of this exercise, the best replica had a water bowl capacity of 2 litres and a discharge volume (at each tipping) of 50mls. Thus at a single filling it could perform 40 hand washes. The rate of flow of water depends on the size of the hole at the end of the spout. The volume of water held in the spout depends on the angle of the mukombe at rest. The position of the holes made for string suspension are critical. The amount of water saving can be critical. A good hand wash with a normal tap (including soaping) may take 500mls of water.

Since 2013, this ideal shaped mukombe has been mass produced by Prodorite, a plastic engineering company in Harare (1).




Dr. Peter Morgan demonstrating mukombe tippy-tap usage

Usage

The simplicity of the device makes it an ideal candidate for use in the garden, inside houses and even in institutions like schools. Mukombe can be mounted anywhere — in outdoor gardens, next to a toilet, even over a sink.


In the garden


Over a sink


Next to a toilet


In a school

Variants

After the first tippy tap by Dr. Jim Watt, other variants have evolved, making use of locally available materials. Instead of a gourd, a plastic container is used and a stick pedal lever is used to tilt the container to allow water to pour out. The following steps explains in detail how to build one such device. There are many different ways to make the tippy-tap, so one can adapt or modify the model to meet requirements.

Step 1: Materials needed to build tippy-tap are:

A 4-5 liter plastic container, a nail, two 2-meter poles, two short sticks of about 1 meter, string, gravel or small stones, and tools to dig.


Materials to build a tippy-tap

Step 2: Find a suitable place in your garden to install the tippy-tap and dig two holes into the ground one meter apart. Erect the two poles in the holes and strengthen the base.


Put poles 0.5 meters into the ground and one meter apart

Step 3: Tie or nail the smaller stick horizontally to the two vertical poles.


Tie a smaller stick horizontally between the two vertical poles

Step 4: Push a nail through the container where you want it to pivot.


Make a pivot hole

Step 5: Make a hole near the cap to let the air in.


Another hole to let air in

Step 6: Make 2-3 holes to allow water to pour out.


2-3 holes to let water pour out

Step 7: Pass a string through the first two holes you made to suspend the container from the horizontal stick.


Pass a string

Step 8: A small notch is made in the center of the horizontal string to prevent the string from slipping away.


A notch in the stick

Step 9: Take a string and tie it to the mouth of the container. This is the main pulling string which will be tied to a stick that will act as a foot peddle.


Pulling string tied to the mouth of the container

Step 10: Use one more small string to tie the main pulling string to the base of one of the vertical poles.


Main string tied to vertical pole

Step 11: Tie the pulling string to the foot peddle.


Main string tied to foot peddle

Step 12: Fill the plastic container with water.


Fill the container with water

Step 13: Dig a hole and fill it with gravel or small stones to soak away water. This not only prevents the formation of a muddy puddle, but also avoids mosquito breeding.


Pit filled with gravel

That’s it. Water starts to pour when the foot peddle is pressed and stops automatically when the pressure on the foot peddle is taken off.


Tippy-tap in action

Here is a nice video showing another subtle variant of tippy-tap.

Improved hygiene

The positive aspect about this device is that it is very affordable, easy to construct, uses very little water and since only soap is touched, hand washing is hygienic. It uses only about 50 millilitres of water to wash a pair of hands compared to 500 millilitres using a mug. Additionally, the used ‘waste’ water can go to plants or back into the water table (2).

Over 1.5 million children under five die each year as a result of diarrhoea (4). It is the second most common cause of child death worldwide (5). Handwashing with soap at critical times – including before eating or preparing food and after using the toilet – can reduce diarrhoea rates by more than 40 per cent (6). A review of several studies shows that handwashing in institutions such as primary schools and daycare centers reduce the incidence of diarrhoea by an average of 30 per cent (7).

Handwashing with soap can reduce the incidence of acute respiratory infections (ARIs) by around 23 per cent (8). Pneumonia, is the number one cause of mortality among children under five years old, taking the lives of an estimated 1.8 million children per year (9).

Rates of handwashing around the world are low. Observed rates of handwashing with soap at critical moments – i.e, before handling food and after using the toilet – range from zero per cent to 34 per cent (10).

In preventing and avoiding these diseases and deaths, a simple device like tippy-tap plays a pivotal role. These neat little hands-free designs prevent bacteria from getting transmitted between users and hence helps to keep hygiene levels high in areas where there is no running water.

References:

  1. https://www.aquamor.info/
  2. https://www.tippytap.org/
  3. https://www.sendacow.org.uk
  4. Prüss-Üstün A, Bos R, Gore F, Bartram J. Safer water, better health: costs, benefits and sustainability of interventions to protect and promote health. World Health Organization, Geneva, 2008
  5. UNICEF (2008). The State of the world’s children 2008.
  6. Curtis, V., and S. Cairncross. 2003. “Effect of Washing Hands with Soap on Diarrhea Risk in the Community: A Systematic Review.” Lancet Infectious Diseases 3: 275–81.
  7. Cochrane 2008 – Ejemot RI, Ehiri JE, Meremikwu MM, Critchley JA. Hand washing for preventing diarrhoea. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD004265. DOI: 10.1002/14651858.CD004265.pub2.
  8. Rabie, T and Curtis, V. (2006): Handwashing and risk of respiratory infections: a quantative systematic review. Tropical Medicine and International Health, 11(3), 258-267.
  9. The State of the World’s Children 2008. Child Survival. UNICEF
  10. Scott B, Curtis V & Rabie, T. 2003. Protecting children from diarrhoea and acute respiratory infections: the role of handwashing promotion in water and sanitation programmes. WHO Regional Health Forum 7, 42–47

Ravindra Krishnamurthy

Ravindra Krishnamurthy is a freelance science writer covering science, tech, the environment, health, food, and culture.

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