Re: [MW:15833] HST Pressure variation in two pressure gauges

Mr.Chinnadurai,

There is no code specifying that, its a simple physics 

P = F/A

F = mass x gravity 

mass = volume x density x gravity

volume = height x area

F = height x area x density x gravity

P = height x area x density x gravity / area

P = height x density x gravity

density of water = 1000 kg/m^3

gravity = 9.81 m/s^2

consider height = 10 m

calculating the above  we get

P = 98,000 kg/ms^2

1 kg/ms^2 = 1 pascal = 1.450377 x 10^-4 psi

calculating this we get 

P = 14.2134 psi almost equivalent to 1 bar.

On Thu, Nov 1, 2012 at 7:11 AM, chinna durai <iarud87@gmail.com> wrote:

Dear Madhan,
                   

 

                 Can you please specify, where in HYDRO code indicate that  10 meter static head  variation pressure difference will be accept 1 bar .



Thanks & Regards,
  Chinnadurai.P

On Wed, Oct 31, 2012 at 12:56 PM, madhan chozhan <madhanchozhan@gmail.com> wrote:

Dear Dasari,

1. Yes there will be variation in pressure gauge reading when they are fitted at different heights because of the general static head difference, Generally for 10 meter static head difference the pressure difference will be 1 bar (14.5 psi).

2. Normally the first step can be 50% the test pressure and then pressure can be increased to the final test pressure by another 5 steps each compensating 10% totaling 100% by 6 steps.

 3. I think socket weld is a circumferential weld as it makes a complete circumference.

On Wed, Oct 31, 2012 at 10:03 AM, srikanth dasari <dasarosyis@gmail.com> wrote:

Dear experts,

1.while performing a Hydro static test in a pipe line/spool at two different elevation for a continuous one line ,one pressure gauge  has found one reading  at one elevation and another pressure gauge has found another reading at another elevation how much can be the pressure variation in the Two pressure gauges as temperature is also a factor how much temp variation can be allowed as per code???

2.How much percentage of  increase in testing pressure can be increased in testing a pipe line for HST for a specific Testing pressure given in the Drawings???  

3.Please clarify whether Socket weld is Circumferential welding or not define types of circumferential joints???

DASARI SRIKANTH

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Thanks & Regards

Srirammadhan

Piping/painting inspector

Great drill Chaaya

Great Ship

Hamriyah Free zone, UAE

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Thanks & Regards

Srirammadhan

Piping/painting inspector

Great drill Chaaya

Great Ship

Hamriyah Free zone, UAE

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