How to Conform to AS 1349 (summary)

8/18/2019 How to Conform to AS 1349 (summary)

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How to conform to AS 1349 (Australian Standard)

Design and construction:

0. General – Protection against corrosion – all parts that are not inherently resistant

to corrosion, must be painted or otherwise treated

1. Case design and construction

1.1 Sizes

1.1.1 Test gauge: Nominal size: min 150mm

150mm, 200mm, 250mm

1.1.2 Industrial gauge: 50mm, 63mm, 80mm, 100mm, 150mm, 200mm,

250mm, 300mm1.2 Material: Specified by the purchaser

1.3 Finish: Non‐reflecting is preferred (otherwise specified by the purchaser)

1.4 Back: Solid or removable back (latter should be adjustable when the

back is removed)

1.5 Dust and splash proofing: Should be dust and splash resistant!

1.6 Window: 80mm and up gauges min. 3mm thick sheet of glass (or other

similar material specified by the purchaser)

Uniform in thickness and free from defects!1.7 Turning radius of direct and surface‐mounting gauges:


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1.8 Mounting of circular surface mounting gauges

1.9 Mounting of circular flush mounting gauges

2. Shank (connector) design and construction

2.1 Material: compatible with the Bourdon tube, suitable for its purpose,

comply with the relevant standards

2.2 Construction: stamped, cast, or machined from bar stock

constructed in one piece, must include hexagon or square

2.3 Accessibility: connection must be long enough (case cannot be touched

by any means)

surface mounting gauges: hexagon or square is far enough

from the rear flange (standard wrench and union nut can be

used effortlessly)


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2.4 Screw threads: nominal sizes of screw threads see below

Thread series must be mated as follows (BSPT=R, BSPP=G):a, R/RC (taper external / taper internal)

b, R/RP (taper external / parallel internal)

c, GB/G (parallel external / parallel internal)

Do NOT mix R and G threads!!!

2.5 Shank dimensions: dimensions of screw thread + hexagon/square + spigot

see below

BSPP (G):


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BSPT (R):

2.6 Seating: For parallel threads (see parallel shank picture above)

seating must be flat, spigot end must be rounded, face may be

chased with one or more concentric grooves

2.7 Seating washer (optional): suitable, solid material, rubber should be avoided

Under 6000kPa leather (not suitable for use with oxygen), red

or grey vulcanized fiber, annealed copper (not suitable for use

with acetylene)

Above 6000kPa annealed copper (not suitable for use with

oxygen), annealed aluminum, metal bonded seals

Measurements are shown below:

2.8 Union connections: optional


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3. Bourdon tube and movement design and construction

3.1 Tube anchorage

3.1.1 Material: compatible with the Bourdon tube, suitable for its purpose,

comply with the relevant standards

3.1.2 Construction: stamped, cast, or machined from bar stock

may be integral with the shank

3.2 Bourdon tube

3.2.1 Material: must be suitable for use with neutral oil, air, water or steam

(brass or bronze (copper alloy), steel, AISI316 SS, Monel)

corrosive or chemically active materials tube and shank need to

withstand them

3.2.2 Mounting: Bourdon tube – anchorage mounting

Bourdon tube – shaft fitting TBW

Joints must be made by soldering, brazing, welding or

screwing

3.3 Movement

Must be mounted on the tube anchorage (or any part that is

integral with the tube anchorage)

4. Dial and pointer design and construction

4.1 Material of pointer and dial: It shall withstand the following withoutcracking, blistering of the applied paint or warping:

a, Temperature of 85C for 10 hours (under dry conditions)

b, Water immersion at 85C for 1 hour

4.2 Pointer specific

Metal or suitable plastic

Can be fixed securely on its spindle

Must be balanced at its center of rotation

The tip shall be as near to the dial as possible

The tip shall lie within the circumference of two concentric

circles drawn through the ends of the shortest graduation lines

(test gauges must have knife‐edge pointers)


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Minimum length of pointers are shown below:

4.3 Pointer stop

May be provided

5. Scale design

5.1 Units: must be clearly marked on the dial in symbol form

Scale factor shall be also marked on the dial right below the unit of

pressure

E.g.: kPa

x 1000

5.2 Ranges5.2.1 Test gauge: Specified by the purchaser

5.2.2 Industrial gauge: See below


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5.2 Scale marking TBW

General: 1, 270 degrees

2, black markings on matt white background

3, if a particular pressure (range) is to be indicated

distinctive colored line on scale

4, increase in pressure clockwise direction

5, increase in vacuum anticlockwise direction

5.2.1 Industrial gauges:

1, no more than 50 scale divisions

2, maximum and minimum values shall be at the

bottom of the gauge

3, scales shall be symmetrically disposed about the vertical

centerline of the gauge4, scales shall not have boundary lines

5.2.2 Test gauges: TBW

5.2.3 Receiver gauges: TBW


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Safety

1. Safety requirements

General – In case of Bourdon tube rupture, no components are projected from

the front of the gauge

1.1 Gauges for use with high pressure gas: maximum scale reading of 2500kPa

and above safety pattern:

A solid, securely mounted baffle wall must be installed between the

Bourdon tube and dial

A blow out device must be fitted to the gauge (blow out pressure

cannot exceed 100kPa)

Pointer spindle hole shall not be too big

Window shall be non‐splintering glass or clear plastic

1.2 Gauges for use with oxygen

TBW

1.3 Gauges for use with acetylene

TBW


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Accuracy, overload

1. Accuracy

1.1 Test gauges: 0.25% of the maximum scale range

1.2 Industrial gauges

1.2.1 Nominal size above 63mm

Between 10‐90% of the maximum scale range max. 1%

Below 10% or above 90% of max. scale range max. 1.5%

1.2.2 Nominal size 63mm and below

At any given point max. 3%

2. Overload

2.1 Test gauges: No overload test is necessary2.2 Industrial gauges: Overload test is a must

Pressure shall be steadily increased from zero to the relevant

value seen below, then steadily decreased to zero (accuracy shall

be monitored).

Note: 16000 kPa ~ 2320 psi

60000 kPa ~ 8702 psi


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Test

1. Test of gauges

1.1 Test apparatus

1.1.1 Test gauges: tested against deadweight testers, manometers, or other

precise and reliable device

Uncertainty of calibration: +‐0.05% of indicated pressure, or 50Pa

(whichever is greater)

1.1.2 Industrial gauges: tested against test gauges, deadweight testers, or

Manometers

Uncertainty of calibration: +‐0.1% of indicated pressure, or 100Pa

(whichever is greater)

If tested against a test gauge, the test gauge must be accurate to

0.25% of its max. scale value

A test gauge’s max. scale value cannot be more than the

industrial gauge’s max. scale value x 1.5

1.2 Test procedures

1.2.1 General: during testing, gauge dial must be in a vertical plane and

midscale point in 12 o’clock position (upright position)

Differently designed gauges must be tested in the position it is

intended to be used (test position shall be marked on dial)1.2.2 Test gauges: TBW

1.2.3 Industrial gauges: at ambient temperature (ideally 20‐22C)

1. gauge is connected to “3.1.2” and to a source of fluid under

pressure

2. gauge test shall be performed in an increasing and also in a

decreasing manner at 3 major scale marks (including the max.

scale value, but excluding 0 (atmosphere))

3. the pointer must be allowed to stop and rest at any given

points, and the instrument casing can be tapped lightly before

the reading is taken

1.3 Test report and record

1.3.1 Test report: it must be attached to every test gauge

Unless requested by the purchaser, test report is not required for

industrial gauges

Test report content:

a, name and address of the testing authority

b, date of test


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c, test report no.

d, serial number of the gauge

e, gauge description

f, gauge position during test

g, mean pressure shown by gauge during test at 3 points (both

increasing and decreasing) and corresponding corrections

(corrections to manometers or deadweight testers)

h, stating the compliance with the relevant clauses of this

standard

j, other client requested information

1.3.2 Test records: If test report is required, the test record must

also be made

a, date of test

b, serial number of the gauge

c, brief description of the gauge (scale graduation intervals,

Bourdon tube material)

d, reference test instrument (manometer etc.)

e, pressure fluid used

f, actual applied pressures and pressures indicated by the gauge

(both increasing and decreasing)

g, gauge position during testh, test temperature

j, test report number

k, stating the compliance with the relevant clauses of this

standard


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Marking and packaging

1. Marking

The following must be visible on the dial:

a, scale

b, scale unit symbol (kPa, psi etc.), and scale factor if applicable

c, if not made of phosphor‐bronze, Bourdon tube material

d, words “Test Gauge”, if applicable

e, words “Absolute Pressure”, if it’s an absolute pressure gauge

f, test position, if different from normal

g, for oxygen gauges TBW

h, for acetylene gauges TBW

j, manufacturer’s (customer’s) name or trademark

If applicable, positive or negative static head indicated on dial

Markings cannot be too obtrusive, and cannot be in the way of the pointer

2. Packaging

Inlet and screwed connection must be protected with a suitable cap

Gauges must be packed individually in a carton or box

To avoid damages during transit, use dry bracing or cushioning material to

limit the free movement of the gauges inside the box.Carton or box must be labelled:

1, size

2, range

3, grade of gauge (accuracy)

Documents

How to Conform to AS 1349 (summary)