Could you let me know the maximum allowable velocity in pipe in your country?

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I wonder the allowable maximum velocity in pipe in other countries.

In Korea, the maximum velocity is 3.0m/sec but I guess it can be increased when we use erosion resistant materials like steel or PVC. I found some countries like Hong Kong, some states in US allow more than 3.0m/sec (ex: 4.5 or 6.0m/sec)

It will be very appreciated all of you let me know the allowable maximum velocity in pipe. If possible, send me your design standard document to my e-mail.

e-mail: yscatfish96@gmail.com or yscatfish@hanmail.net

Thanks in advance.

Best regards,

Yongseok CHOI

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13 Answers

  2. In Russia, the highest speed of wastewater should be taken, m / s: for metal and plastic pipes - 8 m / s, for non-metallic (concrete, reinforced concrete and chrysotile cement) - 4 m / s, for rain sewage - 10 and 7 m / respectively from.

  3. In the UK it varies depending on Velocities can be allowed to increase to 1.0 to 1.5 metres/second, and possibly higher where pipes are not routed in non occupied areas.

  4. In India design manual recommends maximum velocity for liquid flow  at 3.0 m/sec. The same for gas flow is between 15 to 20 m/sec. One has to carefully select the velocity considering the Suspended solids in the water stream. If solids are present like in wastewater, it can cause erosion in metal and plastic pipe even at low velocity. Besides erosion pressure drop is also required to be considered. At higher velocity more energy will be required to pump the fluid. Thus a balance is required to be worked out between pipe size and pumping energy requirement 

  5. Dear All,

    I did mean gravity sewer not pressured water supply pipe. Someone sent me "Urban Drainage 2nd  Edition" and there is a statement for the following;

    Historically, many sewerage systems were designed so that velocity would
    not exceed a specified maximum. This was no doubt a sensible criterion for
    early brick sewers with relatively weak lime-mortar joints. However, research
    has shown that abrasion is not normally a problem with modern pipe mater-
    ials. Perkins (1977) has suggested that no fixed maximum limit is required,
    but where velocities are high (>3 m/s) careful attention needs to be given to:

    When we need to install sewers for storm drainage in steep slope terrain, it often causes the increase of excavation volume due to gentle slope of sewer to meet 3 m/sec (allowable maximum velocity, design standard). And temporary soil retaining wall will be used according to the site situation.

    So I'd like to gather some information about the exceptional cases in other countries. It will be very appreciated you share your experiences or let me know exceptional design standards in your countries.

    Thank you.

  6. In US there is no "maximum" set but traditionally 10 feet/second is used which is quite close to the metric value you had.  Friction is a factor at such velocities so in hydraulic models, a value of 7 feet/second in peak conditions is a value I have used for design.   

  7. In South Africa our guideline is to design for 0.6 m/s and not more than 1.2 m/s. I tried to link to your email to send the guideline, but it seemed to send me around in circles, sorry.

  9. I agree with the others in that a maximum velocity for say 3 m/s should not be regarded as a standard but as a rough rule of thumb for pipe sizing. I can think of situations where 3 m/s would be acceptable and other where even 2 ft/s would be terribly high.

    The goal is to provide adequate pressure for any reasonable situation. The basic question is "for what flow condition should you satisfy the max velocity target?" Is it max day, max hour, max day plus fire flow, average day with a parallel pipe out of service,...?

    Answered on by

  10. The respondents are all quite right. There is no set maximum other than what the constraints are for the system, it's use and engineering specifications. I have managed a long trunk main for potable water that is pumped at up to 1.5m/s. The power costs of the very large pumps are too great for any higher velocity. 

    In the UK with many very old water distribution pipes the concern is for the shear force that has conditioned the film inside each pipe. We have prescribed limits (low ones!) for any discolouration. Therefore velocity changes outside of a diurnal norm are very carefully managed. Unless a dedicated pipeline is designed most water distribution is typically up to 0.5m/s.

  12. Lique Marco Ferrante said, water hammer which usually is not a problem when you have velocities as low as 1 m/s can become a major problem. On the other hand, headloss is proportional to the square of the velocity an so if you jump from 1 m/s to for example 4 m/s the headloss will be 16 times bigger and this can be another major problem (in gravity flow probably you will not have enough head to supply the flow you want or you will not have the necessary pressure for the flow you want; in pumping systems you will need much more energy to overcome such a big headloss that probably it will not be cost effective). Just do the maths!

  13. Limits are not related to material resistance, as you mentioned, but to water hammer effects. Please note that 1 m/s  corresponds to about 10 bars of overpressure for steel pipes (1m/s*1000m/s/(9.8m/s^2)= 100 m=10 bar). So, 6m/s is 60 bars, which seems is a high value to me for water distribution and supply systems.