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TitleGS_EP_PVV_175_EN
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Total Pages28
Table of Contents
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	1. Scope
	2. Reference documents
	3. Cleanliness requirements
		3.1 Classification
		3.2 Extent
	4. Main cleaning methods
		4.1 Cleaning with air (blowing or air flushing)
			4.1.1 Continuous blowing of air
			4.1.2 Quick decompression
		4.2 Cleaning with steam
		4.3 Cleaning with water (water flushing)
			4.3.1 Circulation of water
			4.3.2 Water spray
			4.3.3 High pressure water
		4.4 Mechanical cleaning
			4.4.1 Hand cleaning
			4.4.2 Pipe cleaning with pigs
			4.4.3 Sand blasting
		4.5 Chemical cleaning
			4.5.1 Chemical cleaning without further coating
			4.5.2 Chemical cleaning with final protective coating
	5. Selection of an appropriate cleaning method
		5.1 Approval of the cleaning method(s)
		5.2 Guidelines
		5.3 Rules for cleaning method selection
	6. Application to a specific network to be cleaned
	7. Protection of the devices included in the network
	8. Protection of devices in the vicinity of the network
	9. Air flushing
		9.1 Specific problems of air flushing
			9.1.1 High velocities and large flows
			9.1.2 Large volumes of air
			9.1.3 Air flushing is a hazardous operation
			9.1.4 Air quality
		9.2 Guidelines for the preparation of an air flushing
			9.2.1 Definition of the network to be cleaned
			9.2.2 Calculation of the necessary flow rate in the main header
			9.2.3 Application of the requirements to the existing facilities
			9.2.4 Sketch of the network to be cleaned
			9.2.5 If the quick decompression method has been selected, the pressure release can be obtained by:
			9.2.6 Fragile devices to be removed
			9.2.7  Safety
		9.3 Air flushing procedure
			9.3.1 Continuous blowing method
			9.3.2 Quick decompression method
		9.4 Cleanliness criteria
	10.  Cleaning with steam
	11. Water flushing
		11.1 Specific problems of water flushing
		11.2 Guidelines for the preparation of a water flushing
			11.2.1 Definition of the network to be cleaned
			11.2.2 Calculation of the necessary flow in the main header of the network
			11.2.3  Estimate of the maximum head loss
			11.2.4 Application of the requirements to the existing facilities
			11.2.5 Sketch of the network to be cleaned
			11.2.6 Location of water inlets and outlets
			11.2.7 Additional material and pieces of equipment required
			11.2.8 Fragile devices to be removed
			11.2.9  Quality of water
				11.2.9.1 Stainless steel materials (pipes or vessels)
				11.2.9.2 Carbon steel materials (pipes or vessels)
		11.3  Water flushing procedure
		11.4 Particular cases: water systems
	12. Chemical cleaning
		12.1 General
		12.2 Chemical cleaning of carbon steel pipes
			12.2.1 Cold degreasing
			12.2.2 Rinsing
			12.2.3 Cold pickling (ambient temperature)
			12.2.4 Rinsing
			12.2.5 Neutralisation (ambient temperature)
			12.2.6 Blowing
			12.2.7 Re-assembly and oil flushing Reinstall each piping item using new gaskets according to the VENDORS drawings or specifi
		12.3 Chemical cleaning of stainless steel pipes
			12.3.1 Degreasing
			12.3.2 Rinsing
			12.3.3 Cold pickling (at ambient temperature)
			12.3.4 Rinsing
			12.3.5 Passivation
			12.3.6 Final rinsing
			12.3.7 Blowing
			12.3.8  Oil flushing
		12.4 Chemical cleaning of external surface of stainless steel components
			12.4.1.1 Mechanical cleaning
			12.4.1.2 Pickling and passivation using liquids
			12.4.1.3 Pickling and passivation using pastes
		12.5 Staff protection
	13. Quality control
		13.1 During cleaning
		13.2 Inspection after cleaning
	14. Reassembly
	15. Preservation of cleaned systems
	16. Documentation
		16.1 Prior to cleaning operations
		16.2 Cleaning performed by Vendors
		16.3 Cleaning performed at site
		16.4 Flushing performed at site
			GS EP EXP 105 - PRECOMMISSIONING EXECUTION (APPLICABLE)
                        
Document Text Contents
Page 1

Exploration & Production

This document is the property of Total. It must not be stored, reproduced or disclosed to others without written authorisation from the Company.



GENERAL SPECIFICATION

PIPING VALVES VESSELS

GS EP PVV 175

Cleaning of piping and vessels


04 10/08 General review

03 10/06 GS EP COR 460 integrated

02 10/05 Addition of “EP” root to GS identification

01 10/03 Change of Group name and logo

00 02/01 First issue

Rev. Date Notes

Page 2

Exploration & Production

General Specification Date: 10/2008


GS EP PVV 175 Rev: 04



This document is the property of Total. It must not be stored, reproduced or disclosed to others without written authorisation from the Company.

Page 2/28

Contents

1. Scope .......................................................................................................................4

2. Reference documents.............................................................................................4

3. Cleanliness requirements.......................................................................................5
3.1 Classification......................................................................................................................5
3.2 Extent.................................................................................................................................5

4. Main cleaning methods...........................................................................................5
4.1 Cleaning with air (blowing or air flushing) ..........................................................................6
4.2 Cleaning with steam ..........................................................................................................6
4.3 Cleaning with water (water flushing)..................................................................................6
4.4 Mechanical cleaning ..........................................................................................................7
4.5 Chemical cleaning .............................................................................................................7

5. Selection of an appropriate cleaning method.......................................................8
5.1 Approval of the cleaning method(s) ...................................................................................8
5.2 Guidelines..........................................................................................................................8
5.3 Rules for cleaning method selection..................................................................................9

6. Application to a specific network to be cleaned ..................................................9

7. Protection of the devices included in the network.............................................10

8. Protection of devices in the vicinity of the network...........................................11

9. Air flushing ............................................................................................................11
9.1 Specific problems of air flushing ......................................................................................11
9.2 Guidelines for the preparation of an air flushing ..............................................................12
9.3 Air flushing procedure......................................................................................................14
9.4 Cleanliness criteria ..........................................................................................................15

10. Cleaning with steam..............................................................................................15

11. Water flushing .......................................................................................................16
11.1 Specific problems of water flushing .................................................................................16
11.2 Guidelines for the preparation of a water flushing ...........................................................16
11.3 Water flushing procedure.................................................................................................18

Page 14

Exploration & Production

General Specification Date: 10/2008


GS EP PVV 175 Rev: 04



This document is the property of Total. It must not be stored, reproduced or disclosed to others without written authorisation from the Company.

Page 14/28

• Blanks
Blanks shall be rigidly fixed to the flanges by bolts and nuts in order to prevent them to fly
off when opening the quick opening valve or when the rupture disk blows out.

• Environment protection
The large quantities of dirty air released during the flushing carry particles of sand, rust,
welding rods, etc., which could damage the nearby equipment. Therefore, adequate
protection has to be installed.

9.3 Air flushing procedure
Before performing the air flushing, the following shall be checked:

• Additional pipes, and dummy spools (where required)

• Supports, clamps, restraints, etc.

• Environment protection

and the safety department shall be asked for an authorisation to start the air flushing operation.

9.3.1 Continuous blowing method

• Start the compressor (see particular procedure and Manufacturer requirements).

• Open the valves on the main header to be air flushed.

• Allow the airflow to enter the network up to the calculated flow rate (check by difference
at the outlet of the compressor, before and after).

• If the valve between the compressor and the network to be flushed is a globe valve, and
if the compressor allows for quick changes of flow rates (contact Manufacturer's
representative), changes of flow rates in the line may be made, thus changing the
velocity and removing more quickly the rust and scale incrusted on the surfaces. (This
method may be attempted if the incrustation is important and/or if the pipe has to be very
well cleaned). For normal dirtiness, a continuous blowing at a constant speed should be
sufficient.

9.3.2 Quick decompression method
Check that the network is isolated.

• If a quick opening valve is used, and if the network is designed for a pressure of at least
6 bars, allow the air to enter the network and have the pressure risen up to 6 bars; then
check that all safety measures have been adhered to, and open the valve. If necessary,
this operation shall be repeated several times, until cleanliness criteria are met.

(If the network cannot withstand a pressure of 6 bars, the pressure shall be carefully
checked (add a pressure gauge if necessary) in order that the maximum allowable
pressure in the system be never exceeded).

• If a rupture disk is used, after having checked that safety measures have been taken,
allow the air to enter the network; check continuously the pressure rise, and when the
rupture disk blows out, stop the air inlet in the network. If necessary, the operation shall be
repeated several times, until cleanliness criteria are met.

Page 15

Exploration & Production

General Specification Date: 10/2008


GS EP PVV 175 Rev: 04



This document is the property of Total. It must not be stored, reproduced or disclosed to others without written authorisation from the Company.

Page 15/28

9.4 Cleanliness criteria
They depend upon the final use of the pipe or the vessel. Compressor's suction lines for
instance, have to be far cleaner than drains.

The main criteria are:

• Color of the cloud at the air outlet
At the beginning of the blowing, the cloud is brown (rust colour); it becomes brighter and
brighter as long as the blowing lasts.

• Color of a blank fixed perpendicularly to the flow at the outlet:
An aluminum plate or galvanised metal plate is generally used. After the first blowing, the
plate colour is brown/gray, due to the multiple impacts. The colour becomes brighter and
brighter after each further blowing. (The plate has to be changed after each blowing).

• Number of impacts on a standard plate
When lines have to be very well cleaned (lines upstream a turbine, for example), a plate is
placed on a "tail pipe", and the number of impacts (see an example of standard plate in
figure C) are counted after 3 minutes of blowing.

10. Cleaning with steam
The differences between air flushing and steam blowing are mainly:

• The temperature, which induces thermal expansion/stresses. Therefore, supports, pads,
etc. and material quality have to be checked carefully to ensure they are able to withstand
such temperatures.

• The vacuum pressure induced by steam when it cools down and becomes liquid, if the
network is isolated.

The advantage is the embrittlement of rust, scale, welding slag, etc., created by this change of
temperature.

The steam blowing shall begin by a slow rise of temperature to allow for thermal expansion of
the system (don't forget to drain the condensates at every low point). When the steam
temperature is roughly reached in the pipe, allow the steam to flow at a rate calculated for the
velocity given in section 9.2.2. At the end of the steam blowing (after 5 min to 15 min), the
cleanliness shall be checked according to section 9.4. If another blowing operation is
necessary, let the network cool first (take care of the thermal expansion, and prevent it from
vacuum, drain all low points); the cooling time may be reduced by blowing air through the
system.

When the cleanliness of the pipe meets the requirements, let the system cool down; drain all
low points and, if necessary, dry the network and reassemble (see section 14).

Page 27

Exploration & Production

General Specification Date: 10/2008


GS EP PVV 175 Rev: 04



This document is the property of Total. It must not be stored, reproduced or disclosed to others without written authorisation from the Company.

Page 27/28

BLIND

PILED WASHER
A

SHACKLES

STRING
TO BE FIXED RIGIDLY
TO METALLIC STRUCTURES

STRINGS

PILED WASHERS

SHACKLES

PILED WASHERS

CROSS SECTION AA

D 4" : 2 STRINGS.
D > 4" : 4 STRINGS AT LEAST

<

DiL >
6

A

L

Di



Figure B

Page 28

Exploration & Production

General Specification Date: 10/2008


GS EP PVV 175 Rev: 04



This document is the property of Total. It must not be stored, reproduced or disclosed to others without written authorisation from the Company.

Page 28/28

STEEL PLATE
t = 25 mm

PIPE TO BE CLEANED

DUMMY SPOOL

SUPPORTS WELDED ON
THE DUMMY SPOOL

A

D

C

B

A = 2 D (= 3D for diameters 3 inches and below)

B = D
5
4 C = D

3
4



Figure C

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