OISD RP - 126Amended edition

FOR RESTRICTED CIRUCULATION

No.

SPECIFIC MAINTENANCE PRACTICES FOR ROTATING EQUIPMENT

OISD RECOMMENDED PRACTICE 126First Edition, August 1990

Amended edition, August, 1999

Oil Industry Safety DirectorateGovernment of India

Ministry of Petroleum & Natural Gas

OISD RP - 126 First Edition, August 1990 Amended edition, August, 1999

FOR RESTRICTED CIRCULATION

NO.

SPECIFIC MAINTENANCE PRACTICESFOR ROTATING EQUIPMENT

Prepared by

COMMITTEE ONINSPECTION OF ROTATING EQUIPMENT

OIL INDUSTRY SAFETY DIRECTORATE2ND FLOOR, “KAILASH”

26, KASTURBA GANDHI MARGNEW DELHI - 110 001.

NOTE

OISD publications are prepared for use in the Oil and gas industry under Ministry of Petroleum and Natural Gas. These are the properties of Ministry of Petroleum and Natural Gas and shall not be reproduced or copied and loaned or exhibited to others without written consent from OISD.

Though every effort has been made to assure the accuracy and reliability of data contained in these documents, OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from their use.

These documents are intended only to supplement and not replace the prevailing statutory requirements.

Note 1 in superscript indicates the modification/ changes/addition based on the amendments approved in the 17th Safety Council meeting held in July, 1999.

FOREWORD

The Oil Industry in India is 100 years old. Because of various collaboration agreements, a variety of international codes, standards and practices have been in vogue. Standardisation in design philosophies and operating and maintenance practices at a national level was hardly in existence. This, coupled with feed back from some serious accidents that occurred in the recent past in India and abroad, emphasized the need for the industry to review the existing state of art in designing, operating and maintaining oil and gas installations.

With this in view, the then Ministry of Petroleum & Natural Gas, in 1986, constituted a Safety Council assisted by Oil Industry Safety Directorate (OISD), staffed from within the industry, in formulating and implementing a series of self regulatory measures aimed at removing obsolescence, standardising and upgrading the existing standards to ensure safe operations. Accordingly, OISD constituted a number of Functional Committees of experts nominated from the industry to draw up standards and guidelines on various subjects.

The present document on “Specific Maintenance Practices of Rotating Equipment” has been prepared by the Functional Committee on “Inspection of Rotating Equipment”. This document is based on the accumulated knowledge and experience of industry members and the various national and international codes and practices. This document is meant to be used as a supplement and not as a replacement for existing codes and practices. It shall be borne in mind that no standard can be a substitute for judgment of a responsible qualified maintenance Engineer. Suggestions are invited from the users, after it is put into practice, to improve the document further.

Suggestions for amendments to this document should be addressed to the Co-ordinator, Committee on “Inspection of Rotating Equipment”, Oil Industry Safety Directorate, 2nd Floor, “Kailash”, 26, Kasturba Gandhi Marg, New Delhi-110 001.

FUNCTIONAL COMMITTEEON

INSPECTION AND MAINTENANCE OFROTARY EQUIPMENTS

List of Members---------------------------------------------------------------------------------------------------------------------------------------

Name Designation & Position inOrganisation Committee

---------------------------------------------------------------------------------------------------------------------------------------1. Sh. K. Gopalakrishanan Sr.Maint.Mgr.CRL Leader

2. Sh.B.P. Sinha Chief Project MGR-MRL Member

3. Sh.Chotey Lal Chief Engineer ONGC Member

4. Sh.R.C. Chaudhary Office Engr.MGR BPCL Member

5. Sh.K.M. Bansal Chief Maint. MGR. IOC Member

6. Sh.Ehsan Uddin Director OISD Member

7. Sh.R.M.N. Marar Jt.Director OISD Member Co-ordinator.

---------------------------------------------------------------------------------------------------------------------------------------

In addition to the above, several other experts from the industry contributed in the preparation, review and

finalisation of this Recommended Practices.

SPECIFIC MAINTEANCE PRACTICES FOR ROTATING EQUIPMENT

CONTENTSSECTION PAGE NO.

1.0 Alignment Systems and Procedures1.1 Scope1.2 System Survey1.3 Planning1.4 Cold Alignment1.4 Hot Alignment1.6 Alignment Tolerance

2.0 Balancing2.1 Scope2.2 General2.3 Selection of Number of Balancing Plane2.4 Balancing Tolerances

3.0 Lubrication System3.1 Scope3.2 Functions of Lubricants3.3 Types of Lubricants

4.0 Preservation of Spare Parts4.1 Scope4.2 General4.3 Preservation of High Value Item4.4 Preservation Procedure for Other Spare Parts4.5 Preservation of Bearings

5.0 References

Appendix IGeneral Safety Precautions

SPECIFIC MAINTENANCE PRACTICES FOR ROTATING EQUIPMENT

1.0 ALIGNMENT SYSTEMS AND PROCEDURES

1.1 SCOPE

This section covers the standard alignment systems and procedures for rotating machinery, precautions to be taken before carrying out the alignment and general alignment guidelines.

1.2 SYSTEM SURVEY

Many steps vital to good machinery alignment should be taken well ahead of the actual ‘cold alignment’. Some of the items, which warrant specific attention, are as follows:

1.2.1 PIPING

A Visual inspection of piping is vital. The following checks should be carried out:

a) Whether the piping is installed in apparent agreement with the design criteria and is complete in all respects as per the drawing.

b) Whether proper placement and adjustment of guides, anchors and supports have been done, whether proper adjustment of tie bolts on expansion joints, correct positioning of hangers have been carried out, whether make up of flanges with gaskets in place have been completed and the bolts tightened.

c) Whether the system is in order so that post alignment piping modifications will not nullify the alignment effort.

d) Nomenclature with flow direction on pipes shall be given. Note 1

1.2.2 Grouting

Grouting should be checked to be sure it is complete and satisfactory.

1.2.3 Foundation bolts

Foundation bolts should be checked for tightness.

1.2.4 Shim packs

Shims are vital link between the machine and foundation. All shim packs should be removed at every machine support just prior to alignment. If the shims have burrs, rust etc. these should be removed and shims without rust, wrinkles, burs, hammer marks and dirt should be used. Use as few shims as possible and replace many thin shims with fewer shims of greater thickness. Stainless steel shims minimise alignment problems associated with shim deterioration.

1.2.5 Checking for Misalignment

Misalignment should be checked in the following manner. A dial indicator should be mounted on the machine support with the indicator stem resting on the sole plate. Watch the indicator as the hold-down bolts are loosened. If movement of the indicator is more than 0.025 to 0.05 mm, it is an indication of a problem that must be defined and eliminated. Remove the shim pack and check with feeler gauges to be certain the machine support is parallel with the sole plate. If not, regrout, re-machine the support or prepare tapered shims.

1.2.6 Checking the Causing for distortion

Test for gross distortion of casing can be made when shim packs are checked in the following manner:

a) With three supports tightened down, remove the shim pack from the fourth support.

b) Determine the total thickness of the shim pack and record the dimension.

c) Using feeler gauges, determine the distance from the sole plate to the machine support. Measure the dimension.

d) Subtract the feeler gauge dimension from the shim pack thickness. This is the total deflection of the machine casing with no support at the corner being checked.

e) Repeat the procedure at each of the four supports and compare the deflection of each. Gross differences in deflections at any of the four supports is an indication of probable casing distortion.

1.2.7 Checking for piping strain

Piping strain is seldom detectable by visual observation. However, gross problems can be detected by the following tests. Following the check of casing distortion, place dial indicators on the machine to monitor both vertical and horizontal movement of the casing or shaft. Loosen all the hold down bolts. If the machine moves more than the average observed when checking individual supports, it is obviously the result of an external force, i.e. the piping.

1.2.8 Bearings

Ensure that the bearings are properly installed in the machines and they are lubricated. Also check the bearing covers for proper tightening.

1.3 PLANNING

Alignment program should be properly planned in order to achieve good results within minimum time. Plans should include:

a) Determination of the desired placement of the shafts (cold settings) considering anticipated thermal growth of the various components. Definition of movement of shafts within bearing clearances, hydraulic loading and any other factors expected to produce relative movement of shaft center when the machines are operated.

b) Determining the sequence of alignment for multi unit trains. For two component trains determine which of the two machines is to be moved.

c) Selecting a specific method for determining relative shaft positions.

d) Deciding on tolerances for theoretical cold alignment settings.

e) Ensuring the quality of alignment bracket, dial indicators and shims required for alignment.

f) Making provisions for permanent recording of alignment data.

g) Ensuring that jack bolts are provided and they are free for moving the machine for alignment.

1.4 COLD ALIGNMENT

The term ‘cold alignment’ refers to the position of a machine’s shaft center line relative to the shaft center line of a connected machine, with both machines in a non operating or ‘cold condition.

Cold alignment is normally the only check made to directly determine the relative position of the two shafts. Results of the check form the basis for determining shaft alignment during operation.

The face and rim method and the reverse indicator method are commonly used for accurately measuring the shaft alignment between machinery. In the face and rim method, a face (axial) measurement and a rim (radial) measurement determine the angle and position respectively of one shaft relative to another. The reverse indicator method uses two rim measurements, one from each coupling to locate one shaft center line relative to the other. Both the face and rim measurements are to be taken with dial indicators.

The face and rim method of alignment can be carried out by using a single dial indicator for taking the face reading or using two dial indicators for taking the face readings. The use of two dial indicators for taking face readings eliminates the effect of axial movement of the shafts during alignment. Procedure for carrying out the alignment using three dial indicators is as follows:

1.4.1 Alignment measuring procedure -Three dial method

The normal method of alignment measurement for turbomachinery is by using an apparatus with three dial indicators as shown in fig 1. The dial indicator with its axis in a radial direction measures the radial misalignment of the shafts. The two dial indicators with their axis in an axial direction measures the axial misalignment of the shafts. Normally the heaviest or the most centrally placed machine is made the reference for alignment.

1.4.2 Reading of the radial misalignment

Zero the radial indicator in correspondence to the vertical plane as indicated in the figure. Rotate the shaft in the operational direction of rotation and note the gauge readings at 900 intervals. Interpret the readings as positive if the dial indicator rod re-enters its appropriate place and negative if it does not. The readings are to be taken at least twice and ensure that the indicator operates with the rod at half stroke. It is advisable, especially for couplings with spacers, to recheck by moving the apparatus with the indicators from one shaft to the other.

The value of the misalignment in the vertical plane is rv=b/2 where b is the reading effected on the dial indicator after a rotation of 1800.

Such are the values read after a rotation of 900

(W) and 2700 (Z) that their algebraic addition coincides, with the measurement taken after 180oC , i.e. b =W + Z (approx.), while their algebraic semi difference indicates the radial misalignment in the horizontal plane, i.e. values of W’, Z’ and ‘b’, must be considered with their sign.

1.4.3 Readings of the axial misalignment

The axial misalignment of the shafts (angular misalignment of the coupling) is read by means of two offset indicators of 1800 and zeroed to their initial position. For taking the reading of axial misalignment use the two vertically aligned indicators. Zero the indicators. Then rotate both shafts and record the measurements read on the dial indicators for each misplacement of 900 as indicated in figure 4.

Supposing that the two comparators are installed on the flange of the P Shaft (with the indicator button bearing on the flange of the Q shaft) and that the readings are made looking at the unit from left to right, we have the value of the axial misalignment in the vertical plane “av as av = d-g/2. If “av” is negative, the flanges appear open downwards and if av is positive flanges appear open upwards. The value of the axial misalignment angle in the vertical plane is obtained through

tg < v = av/o

The value of the axial misalignment in the horizontal plane as will be

ao = (c-o) --(F-h) ___________

2

If “ao” is negative flanges appear open leftwards. If “ao” is positive flanges appear open rightwards. The value of the axial misalignment angle in the horizontal plane “L” is obtained through tg < O = ao/o. Values of c,d,e,f,g and h must be considered with their sign.

1.4.4 Alignment correction procedure

First perform the correction of axial alignment on the vertical plane. It can be corrected by verifying the height of the shims placed underneath the support plates of the machine. As shown in figures the shims to be removed from underneath of the external support is obtained as follows:

S= av.L

-------------- o

To correct the vertical radial misalignment, lift and lower the machine and without changing its angular position, insert or withdraw a shim from each support plate of the machine feet.

To correct the axial and radial misalignment on a horizontal plane, it is sufficient to horizontally move the machine by turning the set screws of the machine.

1.5 HOT ALIGNMENT

Alignment of machineries changes from ambient to operating conditions. Correction for this can be done in two ways:

a) By calculating the thermal growth of individual machineries and giving allowances for it in the cold alignment.

b) By shutting down a machine which had been allowed to stabilise at temperature, installing dial indicators and taking measurements.

The second procedure should be adopted for pumps where the couplings are readily accessible and indicators can be installed in a matter of minutes. But this method is difficult for high speed machineries where it takes more time to install the indicators by which time the machine gets cooled and a change in alignment takes place. Hence, for these machines first procedure is to be adopted.

1.6 Alignment Tolerance

Alignment tolerance means the misalignment that can be permitted between the driver and the driven shafts. This misalignment is specified at operating pressure and temperature of the driver and driven equipment irrespective of the type of coupling used for power transmission.

Tolerances are as given below:-

1. Maximum radial misalignment shall not exceed 5/100 mm TIR (Total indicator reading).

2. Maximum axial misalignment shall not exceed 5/100 mm TIR (Total indicator reading).

2.0 BALANCING

2.1 SCOPE

This section covers the balancing procedures to be followed in shop after repair jobs and the maximum specific residual unbalance allowed for various rotors.

2.2 GENERAL

Imbalance is basically a very simple problem caused by an asymmetry in the rotating element which results in an offset between the shaft center line and center of mass. This asymmetry can be of center weight distribution or it can be a thermal mechanism which produces uneven heating and bowing of the rotor. Imbalance is nearly always characterised by a high radial vibration at running frequency which may also be accompanied by a high amplitude in the axial direction. This is a normal problem encountered in maintenance and it becomes essential to carry out balancing of rotors and couplings. Guidelines for carrying out balancing are given below:

2.3 SELECTION OF NUMBER OF BALANCING PLANE

It is important to recognise the fact that not all balancing problems can be solved by balancing in a single correction plane. To determine whether single plane or two plane balancing is

required, the ratio of the length of the rotor exclusive of supporting shaft to the diameter of the rotor can be used as a guideline as given in table 2.1

Since the unbalance of a rotor could be in any plane or planes located along the length, it is very difficult to locate the plane. Moreover, it may not always be possible to make weight correction in just any plane. In these conditions, corrections can be made in the convenient planes available. (Follow procedure specified by manufacturer).

2.4 BALANCING TOLERANCES

When machines are being balanced in place, it is customary to use the vibration criteria to determine when an acceptable balance has been attained. API Standard 612 and 617 for special purpose steam turbines and centrifugal compressors respectively specify that “ the maximum allowable unbalanced force at any journal at maximum continuous speed shall not exceed ten per cent of the static loading of the journal”. Both API standards state that the maximum residual imbalance shall not exceed

56347 X (journal static loading, lbs).--------------------------------------------------- Nmc2

Where Nmc = maximum continuous speed.

Another standard for rigid rotors defines the maximum permissible imbalance as 4W/N where W = rotor weight in lbs and N = Rotor Speed rpm.

The more conservative standard depends on the specific rotor’s speed and weight. The API standard will be more conservative for light weight high-speed rotors, while the 4W/N criteria will be more conservative for heavy low speed rotors.

For dynamic balancing of flexible rotor ISO STD 5406 may be referred.

3.0 LUBRICATION SYSTEM

3.1 SCOPE

This section covers the functions and properties of the lubricants and lubrication methods commonly used for rotary equipment.

3.2 FUNCTIONS OF LUBRICANTS

Selection and applications of lubricants are determined by the function they are expected to perform. The principal functions of lubricants are :

1. Control friction2. Control wear3. Control temperature4. Control corrosion5. Insulate (Electric)6. Transmit power (Hydraulic)7. Damper shock (Gears)8. Remove contaminants (Flushing action)9. Form a seal (grease)

3.3 TYPES OF LUBRICANTS

There are mainly two types of lubricants, liquid and semi solid. Both are mineral oil based. Though there are some non-mineral oil based lubricants for special purposes, we will only consider the former for the present.

3.3.1 Properties of liquid lubricants or lube oils

There are hundreds of grades of lube oils which are specified for particular services. The range varies from very heavy i.e. high viscosity oils like gear oils to very light i.e. low viscosity oils like instrument and watch oils.

Normally high viscosity oils are used where the machinery operates at low speeds but high loads or torque. A heavier oil here helps to form a

fairly stable film (which does not sheer easily). Lighter oils are used where the speeds (RPM) are high but the load is less, which forms a thinner film but takes off the heat faster. A thick oil in such cases will form a thick film and creates a ‘drag’ on the parts demanding more work energy. Selection of proper viscosity of the oil for a particular service is very important.

3.3.2 Viscosity Index

This is a property by which an oil retains its viscosity within a narrow range at higher or lower temperatures conditions i.e. the oils does not become thin at high temperatures and thick at lower temperatures. This property is essential in any operating machinery because there is always a variation in operating temperatures from idle to ‘full speed’ operations.

3.3.3 Pour Point

This is the ability of the oil to remain in a fluid state at low temperatures, i.e. it should not congeal or become solid at low temperatures. The necessity of this property is obvious.

3.3.4 Flash Point

This property ensures that oil will not vaporise at higher temperature and ignite.

3.3.5 Acidity

The oil should be of low acidity so as not to corrode the parts.

3.3.6 Oxidation Stability

This is a property which ensures that the oil does not deteriorate due to long periods of storage under exposure to atmosphere.

3.3.7 Addition of additives

Apart from the above key properties mentioned in 3.3.1, there are many other properties specified for specific purposes. Some of them are emulsification number, detergent/dispersant activity, corrosion inhibition, antifoaming activity (foam collapse time) etc. The key properties are achieved by processing the oil in various process units by adding additives. Additives are complex, organic or inorganic substances which are specially compounded. Some of the additives used in lubricants are: Antioxidants (hindered phenols), anticorrosion compounds (dithiophosphates), rust inhibitors, detergents (petroleum sulphenates), antifoam agents

(silicate polymers), demulsifiers, extreme pressure additives (chlorinated paraffin wax), etc.

When a lubricant is to be chosen for any service, the exact conditions to which the lubricant is to be subjected should be known and proper lubricant should be chosen. Just any oil is not a lubricant. In the name of inventory control or variety control do not choose the oil at random. Ensure that the oil selected is exact equivalent as per manufacturer’s recommendation.

4.0 PRESERVATION OF SPARE PARTS

4.1 SCOPE

This section covers the standard preservation procedures to be followed for various rotary equipment spare parts.

4.2 GENERAL

Moisture and oxygen are the main contributors causing deterioration. These may cause rusting, pitting of surface and other forms of deterioration. Dirt and dust also causes deterioration particularly for antifriction bearings. Some components such as rubber etc. are affected by ultra-violet rays and should be kept away from the light. Some instruments in general and electronic instruments in particular requires temperature control for proper preservation. Long cylinder shaft and rotors need to be restored in such a way that permanent deflection does not take place. Tyres require frequent change of position to avoid deformation.

Various preservatives are used for preserving various components such as oil preservations compounded with inhibitor and wetting agent. Anti-corrosive compound such as Servo RP 120 or equivalent can be used as oil preservatives. Asphatic/petroleum base grease such as Indian Oil Servo RP 330 can be used as grease preservative. Ordinary greases containing soap should not be used. Wrapping with water-proof paper is a good method of preserving.

4.3 PRESERVATION OF HIGH VALUE ITEMS

4.3.1 Rotor Preservation

In addition to protecting the rotor from corrosive effect of oxygen and other gases in the atmosphere, the rotor also requires protection against deflection. It is recommended that rotors are to be rotated at least once in three months to avoid sagging on long storage. After the receipt

of rotor at site it should be rotated by 180oC as early as possible.

It should be rotated by 1800 position after three months

It should be rotated by 900 position after three months.

It should be again rotated by 900 position after three months.

This procedure should be continued subsequently. By this method the sag will be altered into two mutually perpendicular planes of the rotor. The rotor parts should be preserved by application of rust stop 184 or equivalent. This is to be sprayed on the machined surfaces of all casing, rotors and diphgrams, etc. The rotor journals should be protected by application of two coats of Asian blue lacquer rust preventive and again wrapped up with two layers of bituminous paper and one layer of polythene sheet and then kept over 12mm thick felt or rubber sheet on the wooden blocks in the pedestal. The remaining portion of the rotors are to be preserved with “Rust stop 184 or equivalent”. The pedestal should be kept on perfectly hard & horizontal surface Note 1.

4.3.2 Rotor Re-preservation

The rotor will require represervation on frequent intervals which can be decided by inspecting the rotor and will depend on environment of protection. The following procedure should be followed for represervation:

For represervation, earlier coating shall be removed by suitable method and subsequent washing of the surfaces by suitable solvents should be done. Mechanical cleaning, if adopted, should not cause any scratches or lines on the journal portion. Care should be taken not to spoil the surface finish.

If any slight corrosion is observed it should be removed with fine emery paper.

After removing corrosion, if any, the surfaces should be degreased with the help of a soft brush or pad moistened with a suitable degreasing agent. Degreasing operation is to be carried out a number of times depending upon the dirt on the surface after which the surface is rubbed dry by a piece of cloth.

Surface prepared for represervation should not be touched by hand.

Preservative should be applied in closed premises not later than 3/5 hours after cleaning and degreasing. Application of preservatives should not be done in humid atmosphere and during short changes in temperature, which may cause sweating of surfaces under preservation.

Surfaces can be coated with the preservative by spray gun, by brush or by dipping. While applying anti corrosive layer, care should be taken to see that the coating is uniform and without overflow or gaps.

Coating should be done in solid smooth layer without lapses bald sports and flaws. Each subsequent layer shall be coated after the preceeding one dries up completely.

Surfaces coated with anti corrosive greases should be additionally protected with two layers of waxed paper.

Quality of the anti corrosive layer is checked by visual inspection. Any observed defects should be immediately rectified.

4.3.3 Alternative method of preserving rotor

Another method of preserving the rotors is to store it vertically by suspending in a container sealed and preserved under nitrogen pressure of 0.5 kg/cm2. The pressure gauge indicating the pressure of nitrogen in container should be inspected periodically and positive nitrogen pressure is required to be ensured at all time. Such preservation will not require periodic rotation of turbine rotor and corrosive effects of the atmosphere, accumulation of dust, etc. will be avoided.

4.4 PRESERVATION PROCEDURE FOR OTHER SPARE PARTS

4.4.1 Pump rotor assembly

Pump rotor assembly is preserved by coating them with mineral oil 45 corrosion inhibitor.

4.4.2 Crank shaft

Crank shaft of compressor and diesel engines are protected by painting with bituminous paint on all surfaces except the journals which are protected as indicated in the case of journal of the rotors.

4.4.3 Casing of reciprocating compressors

Casing of reciprocating compressors wherever stocked as insurance spares are painted with bituminous paint except the bore of the cylinder which is preserved by using anti-rust grease.

4.4.4 Pump and compressor spares

All spare parts should be waxed sprayed and wrapped in water proof or VCI papers. These parts should be stored indoor.

4.5 PRESERVATION OF BEARINGS

Bearings which are to be stored for a considerable time must be well protected and to achieve this they should be heated in a bath of good quality petroleum jelly at temperature of 115-1200 C (240-2500 F). The bearings should remain in the bath until they have reached its temperature thereby ensuring that they are free from all moisture. They should then be cooled to approximately 600 C so that the petroleum jelly does not run off when the bearings are taken out of the bath. The rust preventive capacity of the petroleum jelly is increased by mixing it with 3% pure, solid stearic acid.

In all cases the bearings should be wrapped in grease proof paper and then placed in a box which has a lid. The box should be sealed with adhesive tape so that the bearings are well protected against dust. Moisture absorbing sachets should be provided in the box Note 1.

The bearing designation should be written outside of the box so that the contents will be known at a later date without the need to open the box.

5.0 REFERENCED PUBLICATIONS

i) Machinery analysis and Monitoring by John S. Mitchell.

ii) Turbomachinery Handbook published by Hydrocarbon Processing.

iii) BHEL Instruction Manual.

iv) Sawyer’s Turbomachinery Maintenance Handbook-Volume II.

v) Instruction Manual of Hard bearing balancing machines.

vi) Predictive Maintenance Manual of Indian Oil Corporation.

vii) Mechanical balancing of Rotating Bodies BS5265 PART 1981

viii) API 617.

ix) Manual of SKF Bearings.

Appendix-1

1. GENERAL SAFETY PRECAUTIONS

Following general safety precautions should be observed while carrying out any repair jobs on a rotating machinery:

1.1 Maintenance work on any rotating equipment should be started only after obtaining the work permit from the concerned department. Ensure that the equipment is electrically isolated.

1.2 The opening of equipment such as pumps and compressors presents a special safety problem, if proper precautions are not followed. To ensure safety while opening, it is a good practice to treat the equipment as if it were under considerable pressure even though all steps have been taken to relieve the pressure.

1.3 In opening flanges, persons shall first loosen and remove the bolts on the far side away from the men doing the work, with a sufficient number of bolts allowed to remain tight on the near side until the connection can be wedged open. Any unanticipated entrapped pressure will then be dissipated in a direction away from the main doing the work.

1.4 Whenever a pump handling hydrocarbons is taken out of service, all the hydrocarbon lines connected to the pumps should be isolated by blinding. In the case of a back pull out pump, the casing should be blinded by a special fluid instead of blinding the lines.

1.5 Whenever a valve changing, stuffing box packing or checking of piston rings in a

reciprocating compressor is taken up the compressor should be isolated from the system by putting positive blinds.

1.6 Vehicle entry permit should be obtained from the concerned authority before bringing any crane or any other equipment for removing the pump.

1.7 During the sole run of a prime mover fitted with a gear coupling half ensure that the coupling half is properly locked with a lock plate. Otherwise remove the coupling half from the shaft before the sole run of prime mover.

1.8 Rotary equipment should never be allowed to run without coupling guards.

1.9 Teflon tapes should not be used in the threads of plugs and nipples provided in the pump casing of hot pumps. Instead of this, proper high temperature sealants should be applied on the threads of plugs and nipples.

1.10 Persons working on rotating machinery should not wear loose clothes because of the possibility of such items getting caught in moving parts.

1.11 Gaskets and bolts used for making up the flanges should be suitable for the service.

1.12 A display board with clear & bold writing of "EQUIPMENT UNDER MAINTENANCE" should be kept at working site Note1.