+1

Resistance to Bio-degradation and attack

Polyethylene pipe is not known to be subjected to any form of microbiological corrosion. It has excellent resistance to the attack of termites, fungi, insects, or biological agents when it is buried in soil. Polyethylene does not support fungi and even relatively virulent fungi. Polyethylene has been tested for resistance to marine-biological attack and it was found that in their biochemical oxygen demand-type tests, Polyethylene was not utilized by bacteria.

yea i know but i saw in previous post of this thread ppl saying it attack poly..i was quite surprising.. haha

yes, i was told by my plumber. He discourage i use poly pipe for whole house piping... no one heard of it before though.

When you have pump it does not matter much if you split from 1 inch into 1/2 inch since the pump has enough force to push up the water pressure.

When you have no pump logic tells you that the pressure it has is the height of the tank location to its outlets. It is all about gravity and the pressure is usually low due to the limited height. In such case you got to consider the right size of pipe with below consideration:

1. Water that run flat will be slow as such you need bigger pipe. This is from Tank to each individual bathroom before going down.

2. water that runs down has gravity assist therefore need not have to use big pipe, it doesn't help much or at all.

3. The outlets are 1/2 inch, having bigger than half inch does not help the volume flow for pipe coming down with gravity.

In conclusion the proper sizing is:

1. From tank running flat = 1 inch. 1 inch pipe can support 4 nos of 1/2 inch pipes without suffering lost of pressure.
2. From roof to bathroom = 1/2 inch

Note: Area of circle = PI R square.
1 inch pipe area = (22/7*1/2)x(22/7*1/2)=2.47sq"
1/2 inch pipe area =0.617sq"
2.47/0.617=4

@ozak: just saw your post in another thread, you are installing a pump into your current installation.
Actually for my case, I yet to move into my new house, not sure if the water pressure is low or not. After moved in, if cannot accept the water pressure only will add on pump. How should i lay my piping after tank, to "prepare for future pump installation"? From tank branch out 3 pipes to bathrooms now? Or, from tank branch out 1no 1" pipe then only split to 3 nos 3/4" pipe for 3 bathrooms? Mean, before install pump, all bathrooms sharing common inlet. If so, my bathrooms' water pressure without pump will sure low!??

So, don't "prepare for pump" now, isit? When need pump only ask installer to modify piping on the roof?

It is easy method to check if your bathroom have good pressure or not. Ask your plumber to put a gauge on the tap and read what is the psi/bar. Anything above 40psi is good enough. This is general pressure maintain and suggest by forumner here. From here you can know pump or no pump. No need wait.

If don't want pump first, 3 hole from tank and 3 1" pipe to bathroom. Later want pump, just chop of and cap the pipe from tank. PVC pipe easy to modify and change.

Where can I get those Gauge? planning to get one to play around.    Also, how much does it cost anyway?

It is easy method to check if your bathroom have good pressure or not. Ask your plumber to put a gauge on the tap and read what is the psi/bar. Anything above 40psi is good enough. This is general pressure maintain and suggest by forumner here. From here you can know pump or no pump. No need wait.

If don't want pump first, 3 hole from tank and 3 1" pipe to bathroom. Later want pump, just chop of and cap the pipe from tank. PVC pipe easy to modify and change.

It is easy method to check if your bathroom have good pressure or not. Ask your plumber to put a gauge on the tap and read what is the psi/bar. Anything above 40psi is good enough. This is general pressure maintain and suggest by forumner here. From here you can know pump or no pump. No need wait.

If don't want pump first, 3 hole from tank and 3 1" pipe to bathroom. Later want pump, just chop of and cap the pipe from tank. PVC pipe easy to modify and change.

Where can I get those Gauge? planning to get one to play around.    Also, how much does it cost anyway?

Probably can get it at those plumbing hardware shop or those selling tools like compressor air equipment. Not normal hardware shop. Another is at shah alam. Selling pneumatic equipment. Google for SMC.

My working place have a lot this gauge lying around. Curi 1 put in my home too.

Something wrong with existing pipelines. Open tap but no water, plumber said "masuk angin". So, can't know how good the pressure is now.
Then i opt to re-do pipelines, using poly pipe. Since modify pipeline in future when installing a pump cost $$ as need to engage plumber again, i hope to reduce that cost and hassle...

SMC Pneumatics (SEA) Sdn Bhd (HQ)
Lot 36, Jalan Delima 1 /1,       
Subang Hi-Tech Industrial Park,
Batu Tiga, 40000 Shah Alam,
Selangor Darul Ehsan, Malaysia.

This one? Lotsa Gauge lying around? Can curi & sell to us? 

if you want good water flow follow my design.

http://forum.lowyat.net/topic/2271767

by the way..there is no such thing as termite eat poly pipe..i think that contractor just want fool you.

Thanks a lot. This is simple. I am yet to make up my mind if to install a pump.

Feasibility study:
double storey c/w 3baths. Will frequently use 1st floor's bath only. GF's toilet will be for visitor. So, will temporary install 1no water heater (with pump) for the house.
Price difference for water heater with and without pump is around RM 250.
To buy and install a Grundfos pump now RM 1.5k.
=>Not feasible to install pump.

But if i "gamble", combine tomjason and ozak's piping map, MAY BE i do not need to install a pump at all.
may be... still 15 16...

how tall is ideal?

Thanks a lot. This is simple. I am yet to make up my mind if to install a pump.

Feasibility study:
double storey c/w 3baths. Will frequently use 1st floor's bath only. GF's toilet will be for visitor. So, will temporary install 1no water heater (with pump) for the house.
Price difference for water heater with and without pump is around RM 250.
To buy and install a Grundfos pump now RM 1.5k.
=>Not feasible to install pump.

But if i "gamble", combine tomjason and ozak's piping map, MAY BE i do not need to install a pump at all.
may be... still 15 16...

Actually the piping is the same with my drawing. It is still 3 bathroom pipe out from the tank. Not 1 pipe and branch to 3pipe.

You need to know how tall is your tank from your 2nd floor if you cannot using the gauge to check the pressure.

yes, same. but yours c/w check valve & by pass line
still, what is the "at least" height for tank-1st flr?