TYPE 2388 HS-ISO PRESSURE VALVE - Pres-Vac Engineering Aps

OWNER:
INSTRUCTION MANUAL FOR
TYPE 2388
SYSTEM DESCRIPTION
AND OPERATING/MAINTENANCE
INSTRUCTIONS FOR
HS-ISO
PRESSURE VALVE
REV. 4
CUSTOMER INFORMATION
HULL NO.: PRES-VAC REF. NO.:
PRES-VAC ENGINEERING A/S PHONE: +45 4817 4055
SVANEVANG 3-5 TELEFAX: +45 4817 1788
DK-3450 ALLERØD E-mail: presvac@pres-vac.com
DENMARK

INSTRUCTION MANUAL
CONTENTS
HS-ISO PRESSURE VALVE
Page 2 of 25
Rev. 4 October 5, 2004
Page
1. Functional System Description ....................................................................................... 3
1.1. General ................................................................................................................... 3
1.1.1. Ordering Information ................................................................................................ 3
1.2. Design .................................................................................................................... 3
1.2.1. Product Suitability .................................................................................................... 3
1.3. Function .................................................................................................................. 4
1.3.1. Inspection ...............................................................................................................4
1.4. Capacity .................................................................................................................. 4
2. Operating Instructions ................................................................................................... 4
2.1. Installation .............................................................................................................. 4
2.1.1 Service Restrictions .................................................................................................. 4
2.2. Operation ................................................................................................................ 5
2.2.1 Drainage ................................................................................................................. 5
2.2.2. Deposit Indicator ..................................................................................................... 6
2.2.3. Damaged Seals ....................................................................................................... 6
2.2.4. Relief Pressure Adjusting Mechanism........................................................................... 6
2.2.5. Prime Causes For Possible Misbehaviour Of Pressure Valve ............................................ 6
2.2.6. Flushing Port............................................................................................................7
2.2.7. Greasing Nipples ...................................................................................................... 7
2.2.8. Optional Features ..................................................................................................... 8
2.2.9.Change to High Pressure Unit ..................................................................................... 9
3. Maintenance Instructions.............................................................................................. 10
3.1. General .................................................................................................................. 10
3.1.1. Inspection .............................................................................................................. 10
3.2. Corrosion Protection................................................................................................. 10
3.2.1. Coating Repair ........................................................................................................ 10
3.3. Safety Regulations For Maintenance Work .................................................................. 10
3.4. Onboard Verifying Of Set-Pressure............................................................................. 11
3.5. Change Of Blow-down Value ..................................................................................... 11
3.6. Directions For Disassembly / Assembly And Cleaning ................................................... 12
4. Spares ........................................................................................................................... 15
DRAWING NO. 2388-122 (Spare Part Ordering List) ........................................................... 16
5. Trouble-Shooting........................................................................................................... 17
6. Laboratory Report, Summary ........................................................................................ 20
Enclosures:
(1) Flow Charts
(2) Product Review Document
(3) Certificates
(4) Workshop Test Certificate
(5) Maintenance Log Sheet

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
1. Functional System Description
1.1. General
Page 3 of 25
Rev. 4 October 5, 2004
The purpose of this high velocity pressure valve is to provide automatic control of the pressure conditions
during loading, voyage, and ballasting without any manual operation. This is done in such a way that the
efflux velocity of the flow cannot be less than 30 m/s under all flow rates and the actual conditions of
installation. Furthermore, this high velocity pressure valve provides active protection against fire and
explosions on deck in terms of preventing the passage of flame into the protected tank.
1.1.1. Ordering Information
Ordering information according to ISO 15364 should be provided by the customer, if not, it is the
customer´s responsibility that service restrictions, tank pressure limitations, etc. are adhered to.
1.2. Design
The high velocity pressure valve consists of a valve housing with a movable pressure disc, stem, and
valve top. Correct function of the valve is tested, by check-lifting the movable parts, by means of turning
the check-lift handle approximately half a revolution. The check-lift is designed to be self-closing.
WARNING! The attending crew must be familiar with the normal friction in the system in
order to valuate when cleaning is required. Being able to turn the check-lift
handle itself by applying great force does not mean that the moveable parts are
freely moving. If a lever system is used to break the disc free, the gas-passage
way is likely clogged.
This valve is specifically designed with a view to address in-service maintenance, allow inspection of all
vital parts from the outside without the use of tools, and allow wear parts to be replaced in-situ. Essential
functions are reflected by indicators, which are clearly visible from the outside at all times. Thanks to the
patented control system for opening and closing pressures, the valve conforms to requirements for nonhammering
and non-oscillation. The control system combines the simplicity of a weight-loaded design
with the low dynamic pressure drop of a traditional magnet operated design, while adding the in-service
advantages of large net clearances through the gas passage-ways to minimize clogging due to fouling
from residue/condensate. The control system further allows the designer of the venting system to
implement piping of lesser diameter than normal.
1.2.1. Product Suitability
Besides from complying with ISO 15364 a valve design has to be elaborated on in a Product Review
Document, a product drawing, and a manual. The ISO standard does not provide any measures against
which a design can be constructed and considered as being “in conformity”. The standard merely
provides general guidelines and, in particular, recommendations for maintenance. It is exclusively the
owner´s/user´s responsibility to ensure that the valve is adequate for the actual installation and the
usage intended. The owner/user shall do this on basis of:
- A product Review Document describing the valve on basis of ISO 15364.
- A product drawing.
- IMO MSC/Circ. 677/1009 certification.
- Certified service instructions.
- This manual.
It is the owner´s / user´s responsibility to review and establish that the selected valve is correctly sized
according to USCG (VECS) rules and IMO MSC/Circ. 731, and made in a design that will match the
available efforts for maintenance. Various types of valves with different maintenance requirements are
available in the PRES-VAC range with escalating prices for less maintenance requiring types.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 4 of 25
Rev. 4 October 5, 2004
1.3. Function
Pressure build-up in the cargo tank forces the pressure disc from its seat (opening pressure). When the
excessive tank pressure is relieved to a preset level, the disc will re-seat (closing pressure). For details of
the performance characteristics, please refer to the flow charts as enclosed.
The opening and closing pressures are adjustable see section 3.6. Contact PRES-VAC in case adjusting
the pressure-tuning knob is not enough.
1.3.1. Inspection
Due to the relatively large net clearance through the valve, the inner parts are much less sensitive to
deposits than ordinary designs. If no thick deposits are detected by means of the fouling indicator pins
and by visual inspection after removal of the seat-beds in case of any doubts, the valve is in working
condition and no further precautions are necessary. The allowable thickness of deposits before further
inspection and, as appropriate, cleaning is necessary at a total diameter of 12 mm. This measure,
however, is only indicative and does not substitute visual inspection after removal of seat-bed. See
section 2.2.2.
1.4. Capacity
The valve's capacity is rated in standard air. For conversion to maximum loading rates for different
cargoes, please refer to the MASTER'S LOADING CHART as per latest revision of IMO MSC/CIRC. 731.
2. Operating Instructions
CAUTION! Transport, storage and handling of the valve shall take place in upright position.
2.1. Installation
Remove all packing material.
Installation is accomplished by bolting the valve flange to the tank vent pipe's mating flange with a
suitable gasket between. Check-lift to verify unobstructed movement of disc. Follow IMO MSC/Circ. 731
pressure drop calculation during system check to verify correct function.
2.1.1 Service Restrictions:
See CE certificate for:
1. Maximum run-up pipe length.
2. Minimum run-up pipe diameter.
3. Minimum MESG of cargo vapour.
4. Minimum pressure relief setting.
5. Maximum outer ice-layer according to ISO 15364.
6. Maximum fouling level: See the Product Review Document.
7. Maintenance procedures must be observed for proper function of the equipment.

INSTRUCTION MANUAL
2.2. Operation
HS-ISO PRESSURE VALVE
Page 5 of 25
Rev. 4 October 5, 2004
Before loading, discharging, and ballasting the valve must be check-lifted to ascertain free movability of
the valve disc. Correct check-lifting is accomplished by turning the check-lift handle from its vertical
position (fig.1) to its upper position (fig. 2) and back again. The check-lift is self-closing when in proper
maintained condition. If not, it should be cleaned and the rest of the valve inspected/cleaned.
WARNING! The attending crew must be familiar with the normal friction in the system in
order to valuate when cleaning is required. Being able to turn the check-lift
handle itself by applying great force does not mean that the moveable parts are
freely moving. If a lever system is used to break the disc free, the gas-passage
way is likely clogged.
Referring to the International Safety Guide for Oil Tankers and Terminals (ISGOTT) cold weather
precautions include checking the vents regularly, i.e. maintaining the valve operational at all time. These
precautions may be a check-lifting cycle that break the ice coverings and prevents the valve from being
blocked by ice.
The maximum allowed ice thickness for this valve type is 20mm within the breaking capability of the
check-lift.
Fig. 1. Check-lift closed Fig. 2. Check-lift open
2.2.1. Drainage
The valve is self-draining due to large net clearances and no horizontal surfaces on the inside of the
valve.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 6 of 25
Rev. 4 October 5, 2004
2.2.2. Deposit Indicator
To examine for build-up of residue in the valve, unscrew the Plug with the cleaning indicator (pos. 26 on
fig. 18, page 12) and check it for residue thickness. If the residue thickness is over 1 mm, cleaning of the
interior of the valve is necessary. The cleaning method depends on the cargo type. For certain
crystallizing cargoes, heating arrangement may be necessary according to the chemical Code. If the
upper part of the spindle (exposed when check-lifting) is dirty, it must be wiped with a cloth and the
lifting/cleaning procedure repeated until the stem is thoroughly cleaned.
2.2.3. Damaged Seals
It is of utmost importance that the seals are kept in a good condition and are changed before
reassembly, as necessary, to maintain leakage-free operation.
Consequences of damaged or missing seals are as follows:
Type of seal Damaged seal Missing seal
O-rings in flange connections Small leak of cargo or inert gas. Leak of cargo or inert gas.
Small salt water ingress in tank.
O-rings in Disc unit Small leak of cargo or inert gas. Leak of cargo or inert gas.
Small salt water ingress in tank.
Gasket in Plug w. deposit indicator Small leak of cargo or inert gas. Leak of cargo or inert gas.
Small salt water ingress in tank.
Packing in Plug for check-lift Leak of cargo or inert gas. Leak of cargo or inert gas.
Small salt water ingress in tank.
2.2.4. Relief Pressure Adjusting Mechanisms
In order to maintain the relief pressure adjusting mechanisms correct, the Nut (pos. 11 on fig. 18 page
12), must not be dismounted. If dismounted, the relief pressure adjusting mechanism has to be adjusted
again by PRES-VAC or by means of a calibration tool, which can be purchased from PRES-VAC or
elsewhere, see section 3.6.
During normal voyage, the high velocity pressure valve type HS-ISO operates automatically and relieves
pressure caused by thermal variations.
WARNING! As per SOLAS-requirements, check-lifting must be carried out before loading,
discharging and ballasting is commenced. If the valve disc does not move
freely, the cause should be determined and corrected immediately. If a lever is
used, cracking the valve open would not be adequate evidence that it is in
proper working condition. It is likely clogged.
2.2.5. Prime Causes For Possible Misbehaviour Of Pressure Valve
Chattering, hammering, and fluttering are serious situations and known to cause incidents and lack of
flame arresting capability. Reasons may be:
1. Valve is oversized.
2. Valve is sized for maximum flow, but operational flow is only minor and the valve´s reasonable
field of acceptable performance is insufficient.
3. Pressure drop in the upstream piping is too high (the opposite effect on some constructions).
4. The valve is mounted on too small diameter piping, which causes excessive flow turbulence or
pressure fluctuations (resonance).
See section 5, Trouble-shooting.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 7 of 25
Rev. 4 October 5, 2004
2.2.6. Flushing Port
When loading a new cargo for which cleaning of the HS-ISO High Velocity Pressure Valve and vent pipe is
required, this procedure is to be followed:
1) Unscrew the flushing plug (pos. 26 on fig. 18) (only when the tank is depressurized).
2) Connect the hose with the cleaning fluid to the flushing port.
3) Start cleaning.
4) Remove the hose and mount the flushing plug.
Fig. 3: Flushing of HS-ISO Pressure Valve
2.2.7. Greasing Nipples
Fig. 4. : Pressure check-lift with grease nipples
WARNING !
The flushing system may only
be used when it is otherwise
safe to clean the piping.
WARNING !
Be aware that the lubricant is
compatible with the cargo.
*) A clean and check-lifted
valve does not get jammed.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
2.2.8. Optional Features
Optional accessories for special requirements are available.
Page 8 of 25
Rev. 4 October 5, 2004
Fig. 5: Proximity switch for Fig. 6: Fixture for forced Fig. 7: Zero emission kit
stand-by valves closing for PO service for special cargo
Fig. 8: Heating Arrangement Fig. 9: Side mounted Fig. 10: Dual nozzle for im-
(other versions are Gas Freing Cover proved gas disper-
available depending sion of small volume
on size)
Fig. 11: Self closing valve Fig. 12: Gas freeing Cover Fig. 13: Dessicator to prevent
to prevent cargo damage to hygroscopic
escape from sun- cargo
ken vessel

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
2.2.9. Change to High Pressure Unit (Optional)
Page 9 of 25
Rev. 4 October 5, 2004
If the Pressure valve has been delivered with a High Pressure Unit, it is possible to replace the existing
Low pressure Top Unit with a High Pressure.
This is done in the following way (refer to figure 18 on page 12):
1. Remove the screws (pos. 40) and washers (pos. 41) from the top flange connection.
2. Remove the Low pressure upper valve house unit.
3. Mount the High pressure upper valve house unit.
4. When the high pressure unit is in use cover the marked setting on the original pressue valve with
Duct Tape or similar.
The High Pressure Upper valve house unit is marked with the corresponding opening pressure.
The Top Unit not in use, should be stored in vertical up-right position. The best solution is to mount them
on a piece of pipe next to the venting pipes.
Fig. 14: Low Pressure Top Unit Fig. 15: High Pressure Top Unit

INSTRUCTION MANUAL
3. Maintenance Instructions
HS-ISO PRESSURE VALVE
Page 10 of 25
Rev. 4 October 5, 2004
3.1. General
As per SOLAS-requirements, the following service intervals shall be followed as a minimum:
A.
After 6 months of operation, the valve shall be inspected for proper function and, if necessary, be
cleaned. However, we recommend that the valve be inspected more often depending on the cargo type.
If the check-lift handle does not operate absolutely freely, cleaning is required.
B.
After further 6 months of operation, the valve shall be taken apart and cleaned.
Dismounting the upper valve house, see fig. 18 on page 12, provides access to do the necessary
cleaning. It is advantageous to have a spare upper valve house to reduce the time on deck for
maintenance to a bare minimum in regard to keeping the gas-sealing parts in good condition.
3.1.1 Inspection
Due to the relatively large net clearance through the valve, the inner parts are much less sensitive to
deposits than ordinary designs. If no thick deposits are detected by means of the fouling indicator pins
and by visual inspection after removal of the seat-beds in case of any doubts, the valve is in working
condition and no further precautions are necessary.
NOTE! The need for inspection and cleaning may increase depending on operation
conditions, the loading frequency, the type of cargo etc. Making sure that the
exposed part of the stem is clean is the primary maintenance issue.
3.2. Corrosion Protection
When repairing the coating follow the instructions from the producer of the coating type referred to in the
vessel´s general manual.
3.2.1. Coating Repair
Due to the large inner clearance the valve will not block because of surface corrosion, and repairing of
the coating is therefore not necessary from a valve functional aspect, only if the cargo vapor is damaging
to the main body parts.
3.3. Safety Regulations For Maintenance Work
Spark free tools should be used if maintenance work is carried out while the valve is mounted on the
cargo tank.
WARNING! All maintenance work must be carried out with necessary precautions in
regard to the cargo’s flammability and toxicity.
NOTE! Before dismounting the seat bed and replacing with a new one – the tank pressure
should be lowered to the same level as when performing ullage measurement
through an open deck valve.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 11 of 25
Rev. 4 October 5, 2004
3.4. Onboard Verifying Of Set-Pressure
After overhaul, verifying of the set-pressure is recommended if the internals of the pressure disc have
been taken apart, which is normally not required. This can be accomplished by either controlling the pullweight
of the pressure disc with a PRES-VAC Dynamometer and confer with PRES-VAC or use the PRES-
VAC Test Rig, type TR or TRM, see fig. 16 and 17 below.
The actual valve set-pressure is stamped on the valve body.
The Test Rig, type TR or TRM, is used for onboard verifying of the set-pressure as well as measurement
of the leakage rate to ensure compliance with environmental regulations.
For further details on type TR or TRM and Dynamometer, please refer to a separate manual. This
equipment can be purchased from PRES-VAC.
Fig. 16: Test Rig Fig.17: Dynamometer
(Mechanical and Ex versions are also available)
3.5. Change Of Blow-down Value
There are two possibilities of changing the blow-down value for a given HS-ISO valve.
1. Change the setting of the pressure adjusting mechanism (see section 3.6)
2. Change the booster plate.
In case of need for changing an existing HS-ISO valve, please consult PRES-VAC.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 12 of 25
Rev. 4 October 5, 2004
3.6. Directions For Disassembly / Assembly And Cleaning
Normal cleaning and inspection, see fig. 18:
1. Unscrew the Nut (pos. 16).
2. Remove the Valve top (pos. 7).
3. Pull out the Split pin (pos. 15) and unscrew the Nut (pos. 14).
4. Remove the Screws (pos. 40) and Washers (pos. 41) from the top flange connection.
5. Remove the Upper valve house unit.
6. Inspect and clean all parts. Repair or replace damaged parts as appropriate.
6
Fig. 18: Assembly Drawing for Inspection and Cleaning of HS-ISO Pressure Valve
NOTE! For cleaning we recommend a thin lubrication oil and a brush. If damage on any
parts is observed, repair or replacement must take place.
Assembly after normal cleaning and inspection
1. Assembly is done in the opposite sequence.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 13 of 25
Rev. 4 October 5, 2004
Replacement of pressure seat (pos. 3 on fig. 18)
1. If a spare upper valve house unit with seat-bed is available with a fresh seat, lower tank
pressure to ullage gauging level, unbolt seat-bed and replace.
2. Bring used upper valve house unit with seat-bed to work shop and unscrew seat.
This is done in the following way:
1. Unscrew bolts (pos. 12)
2. Pull off the disc house unit including the o-ring (pos. 19)
3. Unscrew the nut (pos. 9)
4. Pull off the pressure adjusting part (pos. 8)
5. Pull off the disc (pos. 4)
6. Unscrew seat by means of a key between the ribs.
7. Clean thread and insert new seat after surface lapping.
Assembly
1. Assembly is done in the opposite sequence.
NOTE: Seat-beds can be re-used from PRES-VAC at cost of lapping and re-coating, as necessary.
In order to maintain the relief pressure adjusting mechanisms correct, the Nut (pos. 11 on fig. 18), must
not be dismounted. If dismounted, the relief pressure adjusting mechanism has to be adjusted by means
of a calibration tool, which can be purchased from PRES-VAC or elsewhere.
Adjusting the pressure adjusting mechanism
The relief pressure adjusting mechanisms are adjustable within the span given for the approved
configuration. This requires the equipment mentioned in section 3.4.
It is done in the following way:
1. Unlock the lock washer (pos. 10) and unscrew the nut (pos. 11)
A. To increase the opening pressure setting, turn the adjusting screw (pos. 6) clock-wise.
B. To decrease the opening pressure setting, turn the adjusting screw anti-clock-wise.
2. Remount the washer (pos. 10), mount the nut (pos. 11) and lock with the lock washer again.
RECOMMENDATION
It is recommended to have a spare upper valve house unit available with a fresh seat. This will enable
replacement in a matter of 1-2 minutes and minimum-leakage alignment is ensured.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 14 of 25
Rev. 4 October 5, 2004
Assembly/disassembly of check-lift
1. Remove the Vacuum unit.
2. Remove the Screw (pos. 38 on fig. 19).
3. Pull out the Plug for the lift (pos. 31) together with the o-ring.
4. Loosen the screw (pos. 39) fastening the Lifter to the Stem for the check-lift.
5. Slide the Lifter (pos. 29) to one of the sides and remove the Key (pos. 30).
6. Before pulling out the Stem for the check-lift (pos. 28) completely, remove the loose parts (Lifter
and Screw).
Assembly of check-lift
1. Assembly is done in the reverse order.
General
Screws and bolts not protected from loosening, should be secured by a suitable adhesive, such as PRES-
VAC part no.: 1323-8.
Fig. 19: Check-lift Assembly
RECOMMENDATION
Fill in the maintenance log sheet in connection with inspection and service. See back of manual.

INSTRUCTION MANUAL
4. Spares
HS-ISO PRESSURE VALVE
Page 15 of 25
Rev. 4 October 5, 2004
There are no class requirements for carrying spares on board. If spares are required, please use the
following procedure:
1. Take a copy of the inserted drawing no. 2388-122.
2. Identify the components and write the required quantities on the part list.
3. Advise builder of ship and new building number.
4. Advise Vessel name.
5. Advise serial number punched into the flange of the valve.
Fax the drawing to our office in DENMARK.
When we have the above information, our files contain all further details.
Our telefax and E-mail are open 24 hours a day
Telefax No........ +45 48 17 17 88
E-mail.............. presvac@pres-vac.com
Our telephone is open during normal office hours
Telephone No.: . +45 48 17 40 55
Our postal address:
PRES-VAC ENGINEERING A/S
Svanevang 3-5
DK-3450 Allerød
Denmark

INSTRUCTION MANUAL
SPARE PART ORDERING LIST
HS-ISO PRESSURE VALVE
Page 16 of 25
Rev. 4 October 5, 2004

INSTRUCTION MANUAL
5. Trouble-shooting
HS-ISO PRESSURE VALVE
Problem Remedy
Page 17 of 25
Rev. 4 October 5, 2004
Tank pressure is too high A.
Check in vessel’s Master Loading Chart according to
IMO MSC/Circ. 731 what the maximum permissible
loading rate is and the corresponding loading rate
with corrections for vapor density and vapor growth
rate. Lower loading rate if necessary.
B.
Check that the valve is clean inside and take care of
maintenance as per Section 3 if necessary.
B.1.
Check that the valve disc is able to travel full stroke
by hand-lifting.
B.2.
Check that pressure seat/disc contact area (width)
is not exceeding manufacturer’s recommendations
to avoid a “aero-dynamic” lock (like blowing
between two sheets of paper) as a consequence of
“home-made” repairs.
C.
Check that the piping is unobstructed by cargo
residue etc.
D.
Check that the pressure-tuning knob has not been
tampered with by use of a calibrated test
instrument.
E.
Contact PRES-VAC to check if the configuration of
magnet-power and booster disc arrangement can
be changed for a more suitable performance for the
actual conditions of installation.
Tank vacuum is too high
A.
Check in vessel’s Master Loading Chart according to
IMO MSC/Circ. 731 what the maximum permissible
discharge rate is. Check that pump is running with
the intended delivery head to avoid unintended high
rates. Lower pump rate if necessary.
B.
Check that the valve is clean inside and take care of
maintenance as per Section 3 if necessary.
B.1.
Check that the valve disc is able to travel full stroke
by hand-lifting.
B.2.
Check that vacuum seat/disc contact area (width) is
not exceeding manufacturer’s recommendations to
avoid a “aero-dynamic” lock (like blowing between
two sheets of paper) as a consequence of “homemade”
repairs.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 18 of 25
Rev. 4 October 5, 2004
Tank vacuum is too high (continued) B.3.
Check that the vacuum disc’s contact area is dry to
avoid a hydraulic lock.
C.
Check that the piping is unobstructed by cargo
residue etc.
D.
Contact PRES-VAC.
Not fully lifting pressure disc:
Due to the relative large venting capacity required
according to USCG regulations on Vapor Emission
Control Systems, which for some cargoes are nearly
doubling the actual loading rate, valves may in fact
be handling far less than designed for. Especially
when the sizing procedure did not allow the VECS
capacity to be present at an elevated tank pressure
just below the maximum working pressure. In other
words; a generous provision for venting capacity is
a problem and the valve performance might appear
as chattering or fluttering and can severely reduce
the lifetime of seats and discs.
The remedy available is to consult PRES-VAC for
guidance on adjusting the opening setting and/or
the configuration of the booster plate arrangement.
In extreme cases, for instance for slop tanks
equipped similar to the main cargo tanks, it may be
necessary to install a dual, small capacity unit with
a differing setting making the too large original
valve a stand-by safety unit for the rare maloperating
event.
The valve is leaking A.
Clean valve discs and seats.
B.
Check pressure check-lift seal.
C.
Overhaul or replace seats and discs as appropriate.
D.
Contact PRES-VAC.
The valve is hammering A.
Check that installation is within the service
restrictions shown in the certification issued by the
CE Notified Body ( FORCE TECHNOLOGY). If not,
contact PRES-VAC.
B.
If the valve is grossly over-sized for the actual
capacity vented, the opening and closing cycle may
reduce the expected lifetime of the sealing parts. If
the differential between the capacity of the valve
based on USCG VCS requirements is too far from
the actual volume vented, the lifetime of the
sealing parts is reduced.

INSTRUCTION MANUAL
HS-ISO PRESSURE VALVE
Page 19 of 25
Rev. 4 October 5, 2004
The valve is hammering (continued) C.
Check Section 2.2.5 on “Valve Misbehaviour.”
Hammering is by definition non-intended full stroke
movement of the pressure disc and should not be
misunderstood for non-fluttering.
C.1.
Hammering is not an issue with vacuum valves as
these are modulating and therefore unstable in the
opening phase. Since flash-back protection is not
connected with a high velocity nozzle, disc
movement is no concern, save from a lifetime
aspect.
D.
Contact PRES-VAC to check if the configuration of
magnet-power and booster disc arrangement can
be changed for a more suitable performance for the
actual conditions of installation.

LABORATORY REPORT - SUMMARY TESTED IN ACCORDANCE WITH MSC/Circ. 677/1009
6. Laboratory Report, Summary
SUBJECT: HS-ISO PRESSURE VALVE
The following report is part of the Instructions Manual as required by MSC/Circ. 677, paragraph 4.3 and
should be kept on board the tanker.
The report contains in a condensed form all conducted tests and results obtained, as well as all further
information required, according to the IMO-rules, MSC/Circ. 677 as amended by Circ. 1009 and ISO
15364.
The complete Laboratory Report and test data including video documentation is on file with Force
Technology, the CE Notified Body. The following tests were completed successfully as indicated on the
attached certificates of Type Approval from Force Technology.
Test
1
2
3
4
5
6
7
Description
Corrosion test
Hydraulic pressure
test
Hammering test
Flow test
Flash-back test
Endurance
burning test
Ice test
MSC/Circ.
677/1009
3.5.1
3.5.2
2.3.6 1
3.3.2
3.3.3.1
3.2.3.2/2.3.6
2.3.4
Remarks:
The corrosion tests were carried out on a test rig as
shown on drawing no. 1194-26. The test results were to
the satisfaction of the Notified body.
The hydraulic tests were carried out on a test rig as
shown on drawing no. 1194-317. The test results were
to the satisfaction of the Notified body.
The hammering tests were carried out on a test rig as
shown on drawing nos. 1194-162 and 1194-163. In no
case did hammering occur on the pipe lengths indicated
in the certificate.
The flow tests were carried out on a test rig as shown on
drawing nos. 1194-148 and 1194-149. The results obtained
appear from the inserted flow curves as enclosed.
The flash-back tests were carried out on a test rig as
shown on drawing no. 1194-159. In no case did flashback
occur.
The endurance burning tests were carried out on a test
rig as shown on drawing no. 1194-158. In no case did
flash-back occur.
The ice test was carried out on a test rig as shown on
drawing no. 1194-161. The test valve was covered with
ice of a thickness of 20-50mm. Hereafter the valve was
check-lifted, and it was seen that the ice broke off at the
outlet, and the valve was fully operative. Heating
arrangements are not required, unless for crystallizing
cargoes.
Additionally, separate flow testing has been performed in accordance with API 2000 Standard because
flow testing as per MSC/Circ. 677/Circ. 1009 and ISO15364 does not automatically qualify for API 2000
requirements since higher pressure and vacuum conditions are necessary for some valve configurations.
Please refer to the attached Certificates of Type Approval from Force Technology.
1
If length-restrictions are violated, the ability to arrest flame is uncertain as fire tests were
performed adhering to the stated pipe configuration.

Drawing no.: 1194-26, Corrosion Test

LABORATORY REPORT - SUMMARY TESTED IN ACCORDANCE WITH MSC/Circ. 677/1009
Drawing no.: 1194-317, Hydraulic Pressure Test
Drawing no.: 1194-162, Hammering test
SUBJECT: HS-ISO PRESSURE VALVE

LABORATORY REPORT - SUMMARY TESTED IN ACCORDANCE WITH MSC/Circ. 677/1009
Drawing no.:1194-163, Hammering test
Drawing no.: 1194-148, Flow Test
SUBJECT: HS-ISO PRESSURE VALVE

LABORATORY REPORT - SUMMARY TESTED IN ACCORDANCE WITH MSC/Circ. 677/1009
Drawing no.: 1194-149, Flow test
Drawing no.: 1194-159, Flash-back Test
SUBJECT: HS-ISO PRESSURE VALVE

LABORATORY REPORT - SUMMARY TESTED IN ACCORDANCE WITH MSC/Circ. 677/1009
Drawing no.: 1194-158, Endurance Burning Test
Drawing no.: 1194-161, Ice Test
SUBJECT: HS-ISO PRESSURE VALVE