ASTM D3305 - 94 (2005)

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Designation: D 3305 – 94 (Reapproved 2005)

Standard Practice for

Sampling Small Gas Volume in a Transformer

This standard is issued under the ﬁxed designation D 3305; the number immediately following the designation indicates the year of

original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A

superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

1. Scope

1.1 This practice covers the sampling of gas from a trans-

former gas space or from a gas-collector relay where the

volume of gas available is small and will not permit the use of

Practice D 2759.

1.2 This practice covers sampling, using a gas-tight syringe

as the sampling apparatus and container.

1.3 If the apparatus to be sampled is found to be under a

negative pressure, the apparatus pressure should be raised by

the addition of nitrogen gas until a positive pressure is

obtained.

1.4 This standard does not purport to address all of the

safety concerns, if any, associated with its use. It is the

responsibility of the user of this standard to establish appro-

priate safety and health practices and determine the applica-

bility of regulatory limitations prior to use.

2. Referenced Documents

2.1 ASTM Standards:

D 2759 Practice for Sampling Gas from a Transformer

Under Positive Pressure

3. Signiﬁcance and Use

3.1 Gases may be formed in oil-ﬁlled electrical equipment

as a result of faults. The type of fault and its severity may often

be inferred from the composition of the gases.

3.2 Gas samples are taken from transformer gas spaces or

from gas-collector relays in order that the composition of the

gas sample may be determined.

3.3 In nitrogen-blanketed transformers, the gases generated

by a fault will partition between the gaseous and liquid phases.

On transformers with gas-collector relays, gas in the form of

bubbles may collect in a gas-collector relay and provide a

means to obtain a gas sample for analysis.

3.4 Do not draw samples from an energized instrument

transformer.

4. Apparatus

4.1 Syringe, gastight, 5-mL, with luer loc termination.

4.2 Stopcock, three-way, plastic.

4.3 Length of PTFE Tubing,

⁄

in. inside diameter.

5. Procedure

5.1 Connect the plastic stopcock to the plastic tubing.

Connect the other end of tubing to a suitable valved entrance to

the transformer gas space or gas-collector relay.

5.2 Open the valve and stopcock so gas space gas can ﬂush

air from valve, tubing, and stopcock. (The stopcock handle

points to the closed port, leaving the other two ports in open

communication.)

5.3 Connect syringe to the stopcock.

5.4 Turn the stopcock handle to allow gas from the gas

space to enter the syringe, taking care that gas pressure does

not eject the plunger completely.

5.5 Turn the stopcock so gas can be expelled from the

syringe through the exhaust port of stopcock by pushing

plunger home.

5.6 Open the stopcock to connect gas space to syringe and

ﬁll syringe. Close the stopcock by turning handle toward the

syringe.

5.7 Close the valve on the gas space.

5.8 Remove the plastic tubing from the valve and stopcock,

leaving the stopcock on the syringe.

5.9 Label the sample, package carefully, and transport to

laboratory for analysis.

6. Keywords

6.1 gas; sampling gas; transformer

This practice is under the jurisdiction of ASTM Committee D27 on Electrical

Insulating Liquids and Gases and is the direct responsibility of Subcommittee

D27.07 on Physical Test.

Current edition approved Oct. 1, 2005. Published November 2005. Originally

approved in 1974. Last previous edition approved in 1999 as D 3305 – 94 (1999)

For referenced ASTM standards, visit the ASTM website, www.astm.org, or

contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM

Standards volume information, refer to the standard’s Document Summary page on

the ASTM website.

ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned

in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk

of infringement of such rights, are entirely their own responsibility.

This standard is subject to revision at any time by the responsible technical committee and must be reviewed every ﬁve years and

if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards

and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the

responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should

make your views known to the ASTM Committee on Standards, at the address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,

United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above

address or at 610-832-9585 (phone), 610-832-9555 (fax), or service@astm.org (e-mail); or through the ASTM website

(www.astm.org).

D 3305 – 94 (2005)

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摘要：

本文详细介绍ASTM D3305 - 94 (2005)标准，该标准主要针对小口径无缝和焊接钢管的技术规范与测试方法进行规定。内容涵盖材料的化学成分、机械性能、尺寸公差、制造工艺以及相关的质量检验要求，确保管材在石油、化工、机械等工业领域的应用安全性与可靠性。通过解读该标准，用户可掌握管材选型、采购验收及质量控制的依据，适用于相关从业人员了解小口径管材的技术标准与合规要求。

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