Capstone Project
Department of Mechanical Engineering
Scope of Works
2012
Project Title:
Self Cleaning Downspout
Date:
11/03/2012
Project Team:
Identifier:
CP–CBU-122
Student workers:
Ravi Mehta, 359 681
Martyn Van Reyk, 359 128
Mark Kortekaas,
Benjamin To, 328 566
Academic supervisor: Colin Burvill
Academic examiner:
Client Organisation:
Peter Lee
Centre for Vocational Building Technology
Km Stone 147 Friendship Highway, Ban Thin, Group 5, Tambon Ban
That, 41150
+66 42248423
External Mentor:
Geoffrey Wheeler
CP–CBU-122
Version: 1, 18/03/2012
1.
Project
Self-Cleaning Downspout
2.
Objectives
The main objective of the Self Cleaning Downspout Project is to design a mechanism that
will remove unwanted contaminants, primarily animal faeces, from the collected water,
providing safe, delicious drinking water for the users. The system must fulfil the following
requirements.
• Can be made from sheet metal of different
thicknesses using hand operated equipment.
• Economical
• Reliable, low maintenance
• Durable – 15 year life span
In reaching these objectives, we will have provided the following outputs to go with our
downspout model;
• Solid models and drawings in Inventor format
and on CVBT title block. PDF
• Down spouts (and gutters if needed) installed
and tested on 3 different roof sizes at University of Melbourne.
• Fab’ instruction sheet tested at a Thai shop.
• Bill of materials compiled; Thai/English
• Processes & tooling spec’d in detail; T/E
• Sheet metal shops identified and evaluated
• Dissemination Materials Readys
o Fab’ instruction sheet published: T/E
o Logo or brand applied to spout
o Packaging/Display designed
o Ads published: print & web T/E
o Pricing issued T/E
3.
Definition of starting point
Water is a wonderful natural resource, which supports life and life processes. However, clean
drinking water supplies are not readily available everywhere around the world, and other
resources apart from municipal supplies can be looked at. Rainwater harvesting is a simple,
effective and clean way to provide drinking water to areas such as rural towns and villages, in
this case, Nong Khai in Thailand.
While well and ground water is prone to be disease infected, rainwater is relatively pure and
safe to drink (Caribbean Environmental Health Institute, 2009). However, it can be prone to
contamination from harmful particles on the roofs and gutters. To avoid this, the system must
divert the ‘first flush’, the initial runoff of catchment water, away from the collected area.
The general aim of the project is to build a downspout system that diverts the contaminated
‘first flush’ in a simple and effective way.
Scope of Works 2012
page 2
CP–CBU-122
As rainfall is abundant, we are told water is not collected for the first two to four weeks and
can assume any debris present will be washed off, leaving gutters clean. Hence, the primary
source of contamination is Enteric Pathogens such as bacteria, viruses and protozoa, present
in animal faeces or dead matter (Australian Health Protection Committee-enHealth, 2009).
While such contaminants may cause gastro-intestinal infection, research from the WHO
(World Health Organisation, 2008) shows reported illnesses are rare. Despite this, it is still
advantageous to remove the floating matter and bacteria from collected rainwater to reduce
health risk as well as improve the aesthetic quality of the water (WHO, 2008). Dead animals
and bacterial growth cause an unpleasant sewage/rotten egg type smell (enHealth, 2009).
Water quality testing is often divided into tests for either chemical or bacterial contaminants.
For general testing, bacterial contaminants are often tested. This is because chemical
contamination is often spread across a greater area and will therefore often be detected prior
to physical testing. Chemical contamination also rarely occurs without an expected pollutant.
Bacterial contamination is often tested by means of a presence/absence (P/A) test because of
reduced costs. These P/A test are only capable of determining whether or not a specific type
of bacteria is present but cannot determine the concentration of these bacteria. A common
method of determining bacterial concentrations is the use of so called H2S strips. These strips
can determine the concentration of H2S, which is expelled by many bacteria. This test
however does not differentiate between harmful and non-harmful bacteria. The H2S method is
outlined by the WHO in 2002 and recommended by their guidelines for drinking water
quality from 2008.
To avoid the first flush, we aim to design a Self-Draining Downspout which automatically
diverts the initial contaminated water (exact volume to be determined). A team of two
students form California Polytechnic State University completed a fairly basic version of such
a system, which diverted the first 60 litres of collected water. The system had the following
design features;
 Use of sheet metal galvanised steel, easy to fabricate in rural areas.
 Tube-design tank to hold 60 litres which attached to the gutter.
 Press fitted cap at bottom of tank to remove sediment once water is collected.
 Large inlet which made the downspout suitable for a variety of gutter sizes.
 Drain at bottom of tank allowed for automatic water removal.
Despite successfully meeting most of their design goals, the team identified various
improvements that could be made;
 Cost of system greatly exceeded the goal of 250 Baht. Cost may be reduced by; using
a cheaper grade of galvanized steel (no. 18 or 19), leaving more time for fabrication,
and using existing scrap pieces of flat metal sheets for fabrication
 The amount required to be diverted (60 litres) proved too conservative. Further
research may give us a better estimation.
 Press fitting cap at the bottom of spout (to be removed for cleaning) caused metal on
metal contact. Dirt captured between the cap and the tank made removal more
difficult, and a redesign of the bottom of the tank may be required.
In addition, we have identified the following improvements possible;
 System required villagers to place blocks underneath tank to raise it to correct height.
It may be possible to construct an easier and more stable method of adjusting tank size
 Absence of any filter of cap at top of tank allowed floating material at top of tank to
enter the collection stream once tank is full. A cap which rises with the tank water
level and blocks of the inlet once tank is full could solve this problem.
Scope of Works 2012
page 3
CP–CBU-122
4.
Task descriptions and Durations - Gantt Chart
21-Feb 22-Mar 22-Apr 22-May 22-Jun 22-Jul 22-Aug 21-Sep 22-Oct
allocated time
Develop project goals
analysing existing system
Research environmental conditions.…
Analyse harmfull materials found in…
Explore possible designs.…
Determine advantages and…
Detailed design of solution
First prototype
Testing
Improvement of system
Retesting/Improving
Final adjustments
Analysing performance of the system
Finalising Report
Scope of Works 2012
page 4
CP–CBU-122
6.
End point
By the end of this project we will have developed an easy to use, durable and economical
downspout system which is can be installed on three different roof sizes in the village of
Nong Khai. We will have determined the amount of rainfall needing to be diverted in the
‘first flush’, tested for harmful contaminants to be removed and designed hardware which
removes unwanted floating material from the collected water. Our system aims to be locally
manufactured, with a bill of materials and fabrication sheet suited to Thai manufacturing, as
well as Dissemination materials such as advertising and pricing available in Thai and English.
7.
Mentor reviews
The major critical stage our external mentor (Mr. Geoffrey Wheeler) will be assisting us with
is the design selection phase. We will present at least three different designs or concepts of
our system, assessed from the choice of materials from our morphological analysis. To help
with the development of these designs, a thorough review of the current literature on
downspouts and diverting systems will be done. Mr Wheeler will help identify the preferred
designs and concepts to take forward.
Scope of Works 2012
page 5
CP–CBU-122
8.
Contractual agreement
We, the membership of student team CP–CBU-122 agree to complete the tasks described in
this document.
If being formally completed for a Client Company (identified on the cover page of this Scope
of Works document) this document has incorporated all reasonable suggestions offered by the
Client Company mentor following that person’s review of an earlier draft of this Scope of
Works document.
SIGNED by the Student Researcher
SIGNED by the Student Researcher
SIGNED by the Student Researcher
SIGNED by the Student Researcher
Scope of Works 2012
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
..................................................
Student Researcher’s signature
..................................................
Student Researcher’s name (print)
..................................................
Student Researcher’s signature
..................................................
Student Researcher’s name (print)
..................................................
Student Researcher’s signature
..................................................
Student Researcher’s name (print)
..................................................
Student Researcher’s signature
..................................................
Student Researcher’s name (print)
page 6
CP–CBU-122
SIGNATURE OF Witness
(Academic supervisor)
Scope of Works 2012
)
)
)
)
)
)
)
..................................................
Academic supervisor’s signature
..................................................
Academic supervisor’s name (print)
page 7
CP–CBU-122
References





Seghal, JD, 2008, Roof-Top Harvesting of Rainwater- A Sustainable Water Resource
in S.E.Asia. 4th International Conference on Sustainable Water Environment,
Singapore
Australian Health Protection Committee. EnHealth, 2011, Guidance on use of
Rainwater Tanks, Canberra
The Caribbean Environmental Health Institute 2009, Rainwater, Catch it while you
can: A Handbook on Rainwater Harvesting in the Carribean, St Lucia
World Health Organization 2008, Guidelines for Drinking Water Quality, Third
Edition Incorporating the First and second Addenda, Geneva
World Health Organization 2002, Evaluation of the H2S Method for detection of fecal
contamination of drinking water
Scope of Works 2012
page 8