Transcript Piping_systems

Introduction to the course
APPT5705
Marine Electric and Plumbing
Systems
General Task
• This course is a project based
• Your task is to design plumbing and
electrical systems for a project boat.
• The chosen boat is Chris Lovegrove
design where you already have done
general arrangement and propulsion
system.
Assignments
Drawings and Reports are split in two areas:
• Plumbing: Drawings and a report with one
due date 4 September 2014
• Electrical: Drawings and a report with one
due date 30 October 2014
For details see the very assignment pack
Piping systems
drawings
Piping systems comprise the
following systems:
- Domestic Hot and Cold Water System
- Sewage and Sanitary System
- Bilge and Deck wash System
- Hydraulic System
- Fuel System, Raw water, Exhaust System
- Ventilation, Heating and Air Conditioning System
- Compressed Air System
- Refrigeration System
- Fire Fighting System
Piping as a part of good design
• Size allocation on preliminary General
Arrangement of the boat is often inappropriate to
accommodate all specified equipment. If it
becomes clear at 80% of building stage the
headache is quite serious.
• Not only the size and placement of equipment
spaces are of importance but also the allocation
of spaces for trunking and piping. Piping and
trunking can take up a surprising amount of
space. Good designer will always allocate
suitable spaces and tolerances within his/her
arrangement. That’s why the ability to PLAN
AHEAD is what makes the designer really good.
Photo gallery
Let we see some photographs from installed
systems:
Please make a guess
• What systems are shown
• What is the material of the pipes and
fittings
Piping design – drawings
• Schematic drawings
It is a general requirement according to most
Classification Societies Rules.
For larger craft many companies adopt the method
of having a separate diagram for each of the
piping systems. It simplifies the work and
minimizes possible mistakes.
For smaller crafts some schematics of the system
can be combined in one drawing. If the system is
simple enough no further drawing could be
required.
Schematic drawings
• The main purpose is to clarify what equipment is
to be installed in the specific system and what is
the connection between them. The size of the
pipes and material should be as well given.
• To give clear view what the system consist of
number of symbols are used. Symbolical image
of pipes is continuous lines normally vertical and
horizontal. Where pipes are crossing each other
but are not in any connection the lines are also
crossing. Connections are represented by a
filled point.
Schematic drawings
Valves, pumps and other
components of the system can be
symbolised as follows:
Other symbols can be used as well
Direction of the flow could be denoted by arrows.
Diagrammatic Positioning
drawing
• On this type of drawing the size of main
components of the systems is scaled to suit
general boat layout. Position of the main
components in the boat is clear. Piping routing is
more or less generalized. The boat components
(boat lines, bulkheads, engine, banks, etc.) are
shown by lightweight lines only for reference.
Each item of the system is denoted by a
number. Drawing should contain a specification
clarifying the meaning of the numbers.
• This type of drawing can replace a detail
drawing for smaller boats and relatively simpler
systems.
Detailed drawings
• This type of drawings is done on base of
schematics. It shows every pipe bend, flanged
joint and every piece of equipment. Many small
boat builders do not use detailed drawing for
pipe work since their workforce can interpret
correctly not to much sophisticated systems on a
small craft. But some areas like engine room
appear to be more and more complex lately.
Positioning and identification of all pipes and
equipment pieces is required. Usually this
information is given in 3 dimensions. CAD
programs are very useful in to prepare a 3D
electronic model.
Scale models
• Another form of representation of piping systems
is by producing a scale model of the whole
vessel or just the engine room. This is an
expensive process and is accepted by large
companies.
• The model is dismountable and it is made in
precise scale usually 1:5 or 1:10. All pipes are
color coded and labeled. The construction
requires very skilled model makers. Each piece
of the model can be used for producing a pattern
for production.
• Most of possible errors are avoided but the
method is too labor consuming though is well
repayable for line production. Since the model is
permanent it can be used for further
modifications.
In-situ manufacture
• The method is often used in small craft
building production. The boat builders
work from a schematic drawing and are
planning the pipe and trunking runs on the
vessel itself. Usually a wire frame work in
built up of 5mm diameter steel rod bent
and welded together.
Design requirements
During the design process of piping system there
is a various aspects to consider. Finally the
installation must be:
• Logical and Practical
• Safe
• Efficient
• Fulfils its specification
• Neat
• Cost Effective
• Serviceable
• Does not interfere with other systems
• Long lasting
Golden Rules
See your handouts
Materials for Piping Systems,
Equipment and fittings
Term ‘fitting’ cover:
• Valves
• Branch and bulkhead pieces
• Reducers
• Elbows
• Junction pieces
• Strainers
• Filters
• Expansion pieces
In summary everything in piping system that is
not pipe and specific item of equipment
General requirements to the materials:
1. Sufficient strength or load carrying ability
at the operating temperature and
pressure
2. Retention of suitable ductility and impact
properties at all operating temperatures
3. Satisfactory corrosion and erosion
resistance to the liquid or gas that it
carries or in contacts
4. Resistance to galling with mating
materials in moving contact
5. Compatibility with other materials in the
system
What factors will influence our choice?
a. The type of the service – specific
chemical content of the liquid or gas
carrying, temperature and pressure
b. Availability of the material and equipment
c. Cost
d. Joining ability or forge ability, cast ability
e. Time availability for purchase, delivery or
manufacture
Materials used for Piping
arrangements:
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Cast Iron
Wrought Iron
Steel
Cooper
Brass and bronze
Stainless Steel
Aluminum Alloys
Rubber
Plastic
Plastics
• Cannot be used for continuous service above
50oC and not acceptable if there is likely to be
fire hazard
• Have a high coefficient of expansion
(8 x steel)
• Have a low modulus of elasticity
(about 10-2 x steel)
Plastic pipes therefore requires many more
supports than cooper
• Although theoretically pipes can be joined with
plastic cement or welding the joints are often not
properly made and leak in time
Corrosion
• Corrosion and erosion are unremitting
enemies. Often they are encountered
simultaneously and the problems they
pose demand consideration when deciding
the choice of material