cashco 4381 Installation, Operation & Maintenance Manual

INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)

ISO Registered Company

IOM-3381/4381

06-17

MODELS 3381 AND 4381

PRESSURE RE DUC ING REGULATORS

SECTION I

I. DESCRIPTION AND SCOPE

Models 3381 and 4381 are pressure reducing regulators used to control downstream (outlet or P2) pressure.
Sizes are 1/4" and 3/8" (DN8 and DN10) for the 3381. Sizes for the 4381 are 1/4", 3/8", and 1/2" (DN8, DN10,
and DN15). The 3381 is a bronze bodied unit; the 4381 incorporates a stainless steel body. With proper trim
utili za tion, both units are suitable for liquid, gaseous and steam service (the 4381 can also be used with various
chemi cals). Refer to Tech ni cal Bul le tins 3381-TB and 4381-TB for specific design conditions and selection
rec om men da tions.

The instructions in this manual will apply to both models, unless otherwise stated.

SECTION II

II. INSTALLATION

CAUTION

For welded installations, all internal trim parts, seals and
diaphragm(s) must be removed from reg u la tor body prior
to welding into pipeline. The heat of fusion welding will
dam age non-metallic parts if not re moved. NOTE: This
does not apply to units equipped with extended pipe
nip ples.

CAUTION

Option-1+6 contains single di a phragm con struc tion. In
the event of diaphragm fail ure, the process flu id will mix
with the load ing fluid. Please alert your rep re sen ta tive so
an al ter na tive product can be se lect ed.

1. An inlet block valve should always be installed.

2. If service application is continuous such that
shut down is not readily accomplished, it is rec­ommended that an inlet block valve, outlet block
valve, and a manual bypass valve be installed.

3. Pipe unions should be installed to allow removal
from piping.

4. An outlet pressure gauge should be located
ap proxi mately ten pipe diameters downstream,
and within sight.

CAUTION

Installation of adequate overpressure pro tec tion is
recommended to pro tect the reg u la tor from overpressure
and all down stream equip ment from damage in the event
of regulator failure.

before installing the reg u la tor. Strainers are
rec om mend ed.

7. In plac ing thread seal ant on pipe ends pri or to
en gage ment, ensure that excess material is
re moved and not allowed to enter the regulator
upon startup.

5. All installations should include a downstream
re lief de vice if the inlet pressure could exceed the
pres sure rating of any downstream equip ment or
the maximum outlet pressure rating of the unit.

6. Clean the pip ing of all foreign material including
chips, welding scale, oil, grease and dirt

8. Flow Direction: Install so the flow direction
match es the arrow cast on the main regulator
body.

9. For best performance, install in well drained
hori zon tal pipe, properly trapped if a steam
service ap pli ca tion.

10 A. Basic Regulator - (Refer to Figure 1, Model 3381

or 4381): Regulator may be rotated around the
pipe axis 360°. Recommended position is with
spring chamber vertical upwards. Orient such
that the spring chamber vent hole does not collect
rain wa ter.

10B. Cryogenic Regulator - Options 3381-5 and 4381-

36 (Refer to Figure 2, Model 3381 or 4381):

a. Recommended installation is with spring

cham ber hanging directly be low the body in a

SECTION III

III. PRINCIPLE OF OPERATION

1. Movement occurs as pressure variations register
on the diaphragm. The registering pressure is
the outlet, P2, or downstream pressure. The
range spring opposes di a phragm movement. As

SECTION IV

ver ti cal down wards orientation. Allows water
to drain; etc.

b. Recommend inert purge gas be supplied to

spring cham ber through vent hole and be
discharged out drain hole.

11. Regulators are not to be buried un der ground.

12. For insulated piping systems, recommendation is
to not insulate regulator.

outlet pressure drops, the range spring pushes
the dia phragm down, opening the port; as outlet
pres sure in creas es, the diaphragm pushes up
and the port opening clos es.

2. A complete diaphragm failure will cause the
reg u la tor to fail open.

IV. STARTUP

CAUTION

The maximum outlet pressure is list ed on the name plate
as the upper range spring pres sure level, and is the
rec om mend ed "upper operative limit" for the sens ing
diaphragm (See Section IV. Startup, Step 7). Higher press­ures could dam age the di a phragm. (Field hydro static
tests fre quent ly de stroy dia phragms. DO NOT HYDRO­STATIC TEST THROUGH AN IN STALLED UNIT; ISO LATE
FROM TEST.)

1. Start with the block valves closed. A by pass
valve may be used to maintain out let pres sure
in the down stream sys tem without changing the
fol low ing steps.

2. Relax the range spring by turning the adjusting
screw counter clockwise (CCW) a minimum of
three (3) full revolutions. This reduces the outlet
(down stream) pres sure set point.

3. If it is a “hot” piping system, and equipped with
a bypass valve, slowly open the bypass valve
to preheat the system piping and to allow slow
ex pan sion of the piping. Ensure proper steam
trap operation if installed. Closely monitor outlet
(down stream) pres sure via gauge to ensure not
over-pressurizing. NOTE: If no bypass valve is

in stalled, extra caution should be used in starting
up a cold system; i.e. do everything slowly.

4. Crack open the outlet (downstream) block valve.

5. Slowly open the inlet (upstream) block valve
ob serv ing the outlet (downstream) pressure
gauge. De ter mine if the regulator is flowing. If
not, slowly rotate the regulator adjusting screw
clockwise (CW) until flow begins.

6. Continue to slowly open the inlet (upstream) block
valve until fully open.

7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream
pip ing system isn't pressurized. If the outlet
(down stream) pressure exceeds the desired
pres sure, close the block valve and go to Step 2,
then return to Step 4.

8. When flow is established steady enough that the
outlet (downstream) block valve is fully open,
be gin to slowly close the bypass valve if installed.

9. Develop system flow to a level near its expected
normal rate, and reset the regulator set point by
turning the adjusting screw CW to increase outlet
pressure, or CCW to reduce outlet pressure.

10. Reduce system flow to a minimum level and
ob serve set point. Outlet pressure will rise from
the set point of Step 9. The maximum rise in
outlet pressure on decreasing flow should not
exceed the stated up per limit of the range spring
by greater than 10%; i.e. 20-80 psig (1.38-5.52
Barg) range spring. (Example: at low flow the
outlet pressure should not exceed 88 psig (6.07
barg), if it does, con sult factory).

CAUTION

IOM-3381/43812

V. SHUTDOWN

1. On systems with a bypass valve, and where
sys tem pressure is to be main tained as the
reg u la tor is shut down, slowly open the bypass
valve while closing the inlet (up stream) block
valve. Fully close the inlet (up stream) block valve.
(When on bypass, the sys tem pres sure must be
con stant ly observed and man u al ly reg u lat ed.
Close the outlet (down stream) block valve.

SECTION V

CAUTION

Do not walk away and leave a bypassed reg u la tor
unattended.

2. If the regulator and system are to both be shut
down, slowly close the inlet (upstream) block
valve. Close the outlet (downstream) valve only
if reg u la tor re mov al is required.

SECTION VI

VI. MAINTENANCE

WARNING

SYSTEM UN DER PRES SURE. Prior to performing any
maintenance, isolate the reg u la tor from the system and
relieve all pres sure. Failure to do so could result in
personal injury.

A. General:

1. Maintenance procedures hereinafter are
based upon re mov al of the regulator unit from
the pipeline where in stalled.

2. Owner should refer to owner's procedures for
removal, handling, cleaning and disposal of
nonreusable parts, i.e. gaskets, etc.

3. Refer to Figure 1, Model 3381 or 4381 for the
basic regulator and Figure 2, Model 3381 or
4381 for the cryo gen ic regulator. Blow-ups of
op tions and the com po si tion seat trim are on
either draw ing.

B. Diaphragm Replacement - Model 3381:

3. Loosen spring chamber (2) by placing wrench
on “flats” and rotating CCW making sure not
to use the flat where the vent hole is located.

4. Remove spring chamber (2), range spring
(17) and spring button (5).

5. Remove the diaphragm subassembly
con sist ing of the pressure plate nut (10), lock
wash er (9), pres sure plate (3), diaphragm
(13), push er plate seal (15) and pusher
plate (4). NOTE: Refer to the quan tity of

dia phragms (13) in cor po rated per the bill
of ma te ri als listing. De pend ing on outlet
pres sure level, multiple metal diaph ragms
may be “stacked”.

6. Loosen pusher plate nut (10) and separate
all parts (3, 4, 9, 13 & 15) of the diaphragm
subassembly.

CAUTION

To prevent damage to body, use soft jaws when securing
the body in a vise. Position so that vise closes over the
inlet and the outlet connections.

WARNING

SPRING UNDER COMPRESSION. Prior to re mov ing the
spring chamber, relieve spring com pres sion by back ing
out the adjusting screw. Fail ure to do so may result in
flying parts that could cause personal injury.

1. Securely body (1) in a vise with the spring
chamber (2) oriented upwards.

2. Relax range spring (17) by turning adjusting
screw (8) CCW until removed from spring
cham ber (2).

IOM-3381/4381

Diaphragm Sub as sem bly

7. Inspect pressure plate (3) to ensure no
de for ma tion due to over-pressurization. If
de formed, replace.

8. Remove diaphragm gasket (14). (If a
composition di a phragm is used there is no
di a phragm gasket (14).

9. Clean body (1) and diaphragm flange. Do not
scratch diaphragm gasket seating sur face.

NOTE: On regulators origi nally sup plied as
“oxygen clean”, Option s 3381-5 & -55, 4381­36 & -55, main tenance must in clude a level
of clean li ness equal to Cash co's clean ing

3

stan dard #S-1134. For regulators originally
sup plied as “cleaned for Phar ma ceu ti cal
and Food applications” Options 4381-37
and 4381-37S, maintenance must include a
level of clean li ness equal to Cashco cleaning
stan dard #S-1576. Con tact fac to ry for details.

10. Reassemble diaphragm subassembly by
plac ing pusher plate seal (15) over thread ed
post of pusher plate (4), placing diaphragm(s)
(13) and pressure plate (3) over the threaded
post. Assure the pressure plate (3) is
placed with curved outer rim down next to
the diaphragm (13) surface. Place a thread
sealant compound on the threads of the
push er plate post (4) prior to tightening the
pusher plate nut (10) to the fol low ing torque
values:

Sizes Diaphragm

ALL

Metal 60 (6.8)

Composition 15 (1.7)

Torque

In-lbs (N-m)

2. For SST body (1) and SST spring chamber
(2), use thread lubricant to minimize po ten tial
of seizing threads.

D. Special Instructions for Diaphragm Removal:

1. If the TFE coated diaphragm (13) is utilized on
the Model 4381, the TFE coating is the wetted
side of the diaphragm.

2. If the Option-2 is utilized, the ad just ing screw
(8) and locknut (11) are re placed with a
handwheel (18) and lock nut (11). With the
Option-22 panel mounting w/hand wheel,
the adjusting screw (8) and lock nut (11) are
re placed with a handwheel (18), lock nut (11)
and a panel mounting nut (19).

3. If the Option-1+6 is utilized with metal
diaphragms, there will be one diaphragm
gasket (14) on top of and one below the
diaphragm(s).

CAUTION

11. For metal diaphragm(s) (13), place dia phragm
gas ket (14) into body (1) re cess (none
re quired for com po si tion di a phragm). Set
di a phragm sub as sem bly into the body.

12. Place the range spring (17) over the pusher
plate nut (10) of the diaphragm subassembly.

13. Place multipurpose, high temperature grease
into de pres sion of spring button (5) where
ad just ing screw (8) makes contact. Set spring
but ton (5) onto range spring (17); en sure
spring button (5) is laying flat on top of spring.

14. Rotate the spring chamber (2) CW by hand
into the threaded portion of the body (1)
ensuring not to cross thread. Continue
ro tat ing CW into the body and tighten
approximately 1/4 turn past initial contact with
the diaphragm. Use caution when tightening
the spring chamber, contact with the wrench
on the vent hole boss may damage it.

15. Reinstall ad just ing screw (8) with locknut (11)
into the spring chamber (2).

16. Pressurize with air and spray liquid leak
de tec tor to test around body (1) and spring
cham ber (2) for leakage. En sure that an outlet
pressure is main tained during this leak test
of at least mid-range spring level; i.e. 20-80
psig (1.4-5.5 Barg) range spring, 50 psig
(3.4 Barg) test pres sure min i mum.

C. Diaphragm Replacement - Model 4381:

1. Procedures are the same as Model 3381.

Option-1+6 contains single di a phragm con struc tion. In
the event of diaphragm fail ure, the process flu id will mix
with the load ing fluid. Please alert your rep re sen ta tive so
an al ter na tive product can be se lect ed.

E. Trim Replacement:

1. Secure body (1) in a vise with the body cap
(6) oriented up and the spring chamber (2)
down wards.

CAUTION

To prevent damage to the body, use soft jaws when
securing body in a vise. Position body so that vise closes
over the inlet and the outlet connections.

2. Loosen and remove body cap.

3. Remove piston spring (7), and piston (16).

Note that the seat and piston guide are
in te gral parts of the body (1) cast ing. Inspect
integral seat and guide for ex ces sive wear,
espe cially at seat sur fac es. Replace if worn,
nicked or de pressed. If integral seat is nicked,
use seat lapping com pound to remove.
Valves equipped with Opt-4 Stabilizer will
have the u-cup stabilizer seal (30) removed
when the piston (16) is removed from body
(1). Remove stabilizer seal (30), if installed.

NOTE: When pis ton (16) assemblies are
used with com po si tion seats, Cashco, Inc.
does not recom mend at tempt ing to remove
the com po si tion seat. If composition seat is
damaged, re place entire piston assembly.

IOM-3381/43814

4. Clean flat mating surfaces of body (1) to body
cap (6) shoulder. Be careful not to scratch
either surface.

5. Clean debris from within the body (1) cavity.
Parts to be reused should be cleaned
ac cord ing to own er's pro ce dures. NOTE:

On regulators orig i nal ly sup plied as “ox y gen
clean”, Options 3381-5 & -55, 4381-36
& 55 main te nance must in clude a level of
clean li ness equal to Cashco's clean ing stan­dard #S-1134. For regulators orig i nal ly
sup plied as “cleaned for Phar ma ceu ti cal
and Food ap pli ca tions” Op tions 4381-37
and 4381-37S, main te nance must include a
level of clean li ness equal to Cashco cleaning
stan dard #S-1576. Con tact factory for

details.

6. If supplied with Opt-4 Stabilizer, install new
stabilizer seal (30) properly oriented onto
piston (16).

7. Slide the piston (16), including stabilizer seal
(30) if supplied, slowly into the body cavity.
Use thumbs to ease stabilizer seal(30) into
the body cavity.

8. Place piston spring (7) over spring hub of the
piston (16).

9. Apply pipe thread sealant to the body cap (6)
threads. Screw body cap (6) into body (1).
When body cap is fully down against body
(1) at the body cap (6) shoulder, impact the
body cap (6) into the body (1). NOTE: When

unit is put into service and pressurized, these
two parts seal metal-to-metal with no gasket.

10. Bench test unit for suitable operation. NOTE:

Regulators are not tight shutoff devices.
Even if pressure builds up beyond set point,
a reg u la tor may or may not develop bubble
tight shutoff. In general, tighter shutoff can
be expected with composition seat.

11. Pressurize with air and spray liquid leak
de tec tor to test around body cap (6) and body
(1) for leak age. Test pres sure should be a
mini mum of 100 psig (6.9 Barg) at the inlet.

SECTION VII

VII. TROUBLE SHOOTING GUIDE

1. Erratic operation; chattering.

Possible Causes Remedies

A. Oversized regulator; inadequate rangeability. A1.

B. Worn piston; inadequate guiding. B. Replace trim ( possible body replacement).
C. Weakened/broken piston spring. C. Replace piston spring. De ter mine if corrosion is causing the failure.

2. Regulator can't pass sufficient flow.

Possible Causes Remedies

A. Regulator undersized. A1.

B. Incorrect range spring (screwing in CW of ad-

justing screw does not allow bringing pressure
level up to proper level).

C. Too much droop. C1.

3. Leakage through the spring chamber vent hole.

Check actual flow conditions, re-size regulator for minimum and maximum flow.

A2.

Increase flow rate.

A3.

Decrease regulator pressure drop; decrease inlet pressure by placing a throttling orifice
in inlet piping union.

A4.

Install next step higher range spring. Contact factory.

A5.

Before replacing regulator, contact factory.

Confirm by opening bypass valve together with regulator.

A2.

Check actual flow conditions, re-size regulator; if regulator has inadequate capacity,
replace with larger unit.

B. Replace range spring with proper higher range. Contact factory.

Review droop expected.

C2.

Contact factory.

Possible Causes Remedies

A. Normal-life diaphragm failure. A. Replace diaphragm.

B. Abnormal short-life diaphragm failure. B1.

Can be caused by excessive chattering. See No. 1. to remedy chatter.

B2.

Can be caused by corrosive action. Consider alternate diaphragm material.

B3.

For composition diaphragms, ensure not subjecting to over-temperature conditions.

B4.

Downstream (outlet) pressure buildup occurring that overstresses diaphragms. Relo­cate regulator or protect with safety relief valve.

IOM-3381/4381

5

4. Sluggish operation.

Possible Causes Remedies

A. Fluid too viscous. A. Heat fluid. Contact factory.

5. Excessive pressure downstream.

Possible Causes Remedies

A. Regulator not closing tightly. A. Inspect the seating. Clean and lap metal seat surfaces; replace if lapping does

B. Downstream block. B. Check system; isolate (block) flow at regulator inlet - not outlet. Relocate regula-

C. No pressure relief protection. C. Install safety relief valve, or rupture disc.

D. Restricted diaphragm movement. D. Ensure no moisture in spring chamber at temperatures below freeze point. Ensure

not remedy. If composition seats are depressed, nicked or embedded with debris,
replace trim.

tor if necessary.

no dust or debris entering vent opening. If rainwater or debris can enter, reorient
regulator.

SECTION VIII

VIII. ORDERING INFORMATION
NEW REPLACEMENT UNIT vs PARTS "KIT" FOR FIELD REPAIR

To obtain a quotation or place an order, please retrieve the Serial Number and Product Code that was stamped on the metal
name plate and attached to the unit. This information can also be found on the Bill of Material ("BOM"), a parts list that was
provided when unit was originally shipped. (Serial Number typically 6 digits). Product Code typical format as follows: (last

digit is alpha character that reflects revision level for the product).

–

NEW REPLACEMENT UNIT:

Contact your local Cashco, Inc., Sales Rep re sen ta tive
with the Serial Number and Product code. With this
information they can provide a quotation for a new unit
including a complete description, price and availability.

CAUTION

Do not attempt to alter the original construction of any
unit without assistance and approval from the factory.
All purposed changes will require a new name plate
with appropriate ratings and new product code to
accommodate the recommended part(s) changes.

–

7

PARTS "KIT" for FIELD REPAIR:

Contact your local Cashco, Inc., Sales Rep re sen ta tive
with the Serial Number and Product code. Identify the
parts and the quantity required to repair the unit from
the ("BOM") sheet that was provided when unit was
originally shipped.

NOTE: Those part numbers that have a quantity indicated

under "Spare Parts" in column "A” reflect minimum
parts required for inspection and rebuild, - "Soft Goods
Kit". Those in column “B” include minimum trim
replacement parts needed plus those "Soft Goods"
parts from column "A".

If the "BOM" is not available, refer to the cross-sectional
drawings included in this manual for part identification
and selection.

A Local Sales Representative will provide quotation for
appropriate Kit Number, Price and Availability.

The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be
construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to
modify or improve the designs or specifi cations of such product at any time without notice.
Cashco, Inc. does not assume responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use and maintenance of any
Cashco, Inc. product remains solely with the purchaser.

IOM-3381/43816

MODEL 3381

Basic Model 3381 with Metal Seat Design

Figure 1:

Composition Seat Design

Repair Parts
Item No. Description Kit B
1 Body
2 Spring Chamber
3 Pressure Plate
4 Pusher Plate
5 Spring Button
6 Body Cap
7 Piston Spring -------- ‡‡
8 Adjusting Screw
9 Lock Washer
10 Pressure Plate Nut
11 Adjusting Screw Locknut
12 Nameplate
13 Diaphragm ----------- ‡‡
14 Diaphragm Gasket(s) ‡‡
15 Pusher Plate Gasket ‡‡
16 Piston ----------------- ‡‡
17 Range Spring
18 Handwheel
19 Mounting Nut

Option-5 Cryogenic Model 3381, Metal Seat Design

Figure 2:

(NOTE: Mount in Horizontal line with

Adjusting Screw down as shown.)

Option-20, Dome Loaded

Option-22 Panel Mounting

(Handwheel portion is same as Option-2 Handwheel)

Spring Chamber Thread 3/4"-16 UNF-2A

IOM-3381/4381

7

Basic Model 4381 with Metal Seat Design

Figure 1:

MODEL 4381

(NOTE: Mount in Horizontal line with

Adjusting Screw down as shown.)

Figure 2:

Option -36 Cryogenic Model 4381 with Metal Seat Design

Repair Parts

Item No. Description Kit B
1 Body
2 Spring Chamber
3 Pressure Plate
4 Pusher Plate
5 Spring Button
6 Body Cap
7 Piston Spring ---------------- ‡‡
8 Adjusting Screw
9 Lock Washer
10 Pressure Plate Nut
11 Adjusting Screw Locknut
12 Nameplate
13 Diaphragm ------------------- ‡‡
14 Diaphragm Gasket --------- ‡‡
15 Pusher Plate Seal ---------- ‡‡
16 Piston ------------------------- ‡‡
17 Range Spring
18 Handwheel
19 Mounting Nut
21 Thrust Bearing
22 Upper Bearing
23 Lower Bearing
30 U-Cup ------------------------- ‡‡

(Handwheel portion is same as Option-2 Handwheel).

Option-22 Panel Mounting

Option-22 NOT available with Option-80.
Spring Chamber Thread 3/4"-16 UNF-2A

Composition Seat

with Option -4 Stabilizer

Option-80, High Pressure

Spring Chamber Construction

IOM-3381/43818

ATEX 94/9/EC: Explosive Atmospheres and Cashco Inc. Regulators

NOTICE

Only for Product Codes wherein hazard
category ATEX has been selected.

These valves satisfy the safety conditions according to EN 13463-1 and EN 13463-5 for equipment group IIG 2 c.

Caution: Because the actual maximum temperature depends not on the equipment itself, but upon the fluid temperature, a
single temperature class or temperature cannot be marked by the manufacturer.

Specific Precaution to Installer: Electrical grounding of valve must occur to minimize risk of effective electrical discharges.

Specific Precaution to Installer: Atmosphere vent holes should be plugged to further minimize the risk of explosion.

Specific Precaution to Maintenance: The Valve Body/ Housing must be regularly cleaned to prevent buildup of dust deposits.

Specific Precaution to Maintenance: Conduct periodic Continuity Check between Valve Body/ Housing and Tank to minimize
risk of electrical discharges.

Attention: When repairing or altering explosion-protected equipment, national regulations must be adhered to. For maintenance
and repairs involving parts, use only manufacturer's original parts.

ATEX requires that all components and equipment be evaluated. Cashco pressure regulators are considered components.
Based on the ATEX Directive, Cashco considers the location where the pressure regulators are installed to be classified
Equipment-group II, Category 3 because flammable gases would only be present for a short period of time in the event of a leak.
It is possible that the location could be classified Equipment-group II, Category 2 if a leak is likely to occur. Please note that the
system owner, not Cashco, is responsible for determining the classification of a particular installation.

Product Assessment

Cashco performed a conformity assessment and risk analysis of its pressure regulator and control valve models and their
common options, with respect to the Essential Health and Safety Requirements in Annex II of the ATEX directive. The details
of the assessment in terms of the individual Essential Health and Safety Requirements, are listed in Table 1. Table 2 lists all of
the models and options that were evaluated and along with their evaluation.

Models and options not listed in Table 2 should be assumed to not have been evaluated and therefore should not be selected
for use in a potentially explosive environment until they have been evaluated.

Standard default options for each listed model were evaluated even if they were not explicitly listed as a separate option in the
table. Not all options listed in the tables are available to all models listed in the tables. Individual TB’s must be referenced for
actual options.

When specifying a regulator that is to be used in a potentially explosive environment one must review the evaluations in Table 1
and 2 for the specific model and each and every option that is being specified, in order to determine the complete assessment
for the unit.

A summary of the models and options found to have an impact on ATEX assessment due to potential ignition sources or other
concerns from the ATEX Essential Health and Safety Requirements, are listed below.

1. The plastic knob used as standard on some models, (P1, P2, P3, P4, P5, P7, 3381, 4381, 1171, and 2171) is a
potential ignition source due to static electricity. To demonstrate otherwise, the knob must be tested to determine
if a transferred charge is below the acceptable values in IEC 60079-0 Section 26.14 (See items 25, 27, and 28 in
Appendix A). Until the plastic knob has been shown to be acceptable, then either the metal knob option, or a preset
outlet pressure option is required to eliminate this ignition source (See items 45 and 64 in Tables).

2. The pressure gauges offered as options on a few of the regulator models (DA’s, P1-7, D, 764, 521), use a plastic
polycarbonate window that is a potential ignition source due to static electricity. To demonstrate that the gauges are
not a potential source of ignition, the gauges would need to be tested to determine if a transferred charge is below

IOM-3381/4381

9

indicating the gauge is compliant with the ATEX Directive (See items 26, 27, and 28 in Appendix A). Until compliance
is determined, regulators should not be ordered with pressure gauges for use in potentially explosive environments.

3. Tied diaphragm regulators with outlet ranges greater than 100 psig should be preset to minimize the risk that improper
operation might lead to an outboard leak and a potentially explosive atmosphere (See item 6 in Table 1).

4. Regulators must be ordered with the non-relieving option (instead of the self-relieving option) if the process gas they are
to be used with is hazardous (flammable, toxic, etc.). The self-relieving option vents process gas through the regulator
cap directly into the atmosphere while the non-relieving option does not. Using regulator with the self- relieving option
in a flammable gas system could create an explosive atmosphere in the vicinity of the regulator.

5. Regulators with customer supplied parts are to be assumed to not have been evaluated with regard to ATEX and thus
are not to be used in a potentially explosive environment unless a documented evaluation for the specific customer
supplied parts in question has been made. Refer to Table 1 for all models and options that have been evaluated.

Product Usage

A summary of ATEX related usage issues that were found in the assessment are listed below.

1. Pressure regulators and control valves must be grounded (earthed) to prevent static charge build-up due to the flowing

media. The regulator can be grounded through any mounting holes on the body with metal to metal contact or the
system piping can be grounded and electrical continuity verified through the body metal seal connections. Grounding
of the regulator should follow the same requirements for the piping system. Also see item 30 in Table 1.

2. The system designer and users must take precautions to prevent rapid system pressurization which may raise surface

temperatures of system components and tubing due to adiabatic compression of the system gas.

3. Heating systems installed by the user could possibly increase the surface temperature and must be evaluated by the

user for compliance with the ATEX Directive. User installation of heating systems applied to the regulator body or
system piping that affects the surface temperature of the pressure regulator is outside the scope of this declaration and
is the responsibility of the user.

4. The Joule-Thomson effect may cause process gases to rise in temperature as they expand going through a regulator.

This could raise the external surface temperature of the regulator body and downstream piping creating a potential
source of ignition. Whether the Joule-Thomson effect leads to heating or cooling of the process gas depends on
the process gas and the inlet and outlet pressures. The system designer is responsible for determining whether the
process gas temperature may rise under any operating conditions. If a process gas temperature rise is possible under
operating conditions, then the system designer must investigate whether the regulator body and downstream piping
may increase in temperature enough to create a potential source of ignition.

The process gas expansion is typically modeled as a constant enthalpy throttling process for determining the temperature change.
A Mollier diagram (Pressure – Enthalpy diagram with constant temperature, density, & entropy contours) or a Temperature –
Entropy diagram with constant enthalpy lines, for the process gas, can be used to determine the temperature change. Helium
and hydrogen are two gases that typically increase in temperature when expanding across a regulator. Other gases may
increase in temperature at sufficiently high pressures.

Product Declaration

If the above issues are addressed by selecting options that do not have potential sources of ignition, avoiding options that
have not been assessed, and by taking the proper usage issue precautions, then Cashco regulators can be considered to be a
mechanical device that does not have its own source of ignition and thus falls outside the scope of the ATEX directive.

Cashco, Inc.
P.O. Box 6
Ellsworth, KS 67439-0006
PH [phone]
Fax. # [phone]
www.cashco.com
email: [email protected]

Printed in U.S.A. IOM-3381/4381

Cashco GmbH
Handwerkerstrasse 15
15366 Hoppegarten, Germany
PH [phone]
Fax. No. [phone]
www.cashco.com
email: [email protected]

Cashco do Brasil, Ltda.
Al.Venus, 340
Indaiatuba - Sao Paulo, Brazil
PH [phone]
Fax. No.
www.cashco.com
email: [email protected]

IOM-3381/438110