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K-150 critical orifice kit a1

Critical Orifice Kit --- K-150

  • $377.00

Meets or exceeds the following methods/laws/requirements:


US EPA Method 5:

  • Section (Selection of Critical Orifices)
  • Section 16.2.2 (Critical Orifice Calibration)

Product Description

Critical Orifices are used to calibrate the dry gas meter (DGM) of various metering consoles.

This calibration instrument is approved by the US EPA as calibration standard for calibrating a dry gas meter, in place of the wet test meter stated in Section 16.1 of the US EPA Method 5, provided that the critical orifices are selected, calibrated, and used in accordance with the instructions included in Section 16.2.1 of the US EPA Method 5.

This product connects to the following (non-exhaustive) list of products from Aer Sampling:

  1. Aer Sampling Metering Consoles (sample inlet)
Other Applicable Documents:


Product Specifications

Connection: 1/2-inch quick connect

Material: Brass with Ruby orifice

Sizes (nominal):

Catalog ID


Orifice diameter

Choked flow rate

inch mm cfm LPM
PN-738 400
0.0400 1.0160 0.31 8.79
PN-739 480
0.0480 1.2192 0.46 12.97
PN-740 550 0.0550 1.3970 0.60 17.08
PN-741 630 0.0630 1.6002 0.80 22.61
PN-742 730 0.0730 1.8542 1.09 30.94

Weight (Gravitational):
 1.5 lbs / ~0.7 kg

Packing Dimensions (Length x Width x Height):
English (inch): 10.0 x 8.0 x 3.0
Metric (cm): 25.2 x 20.1 x 8.0

Other Information

Avoid vibration and/or shock.

Calibration of Critical Orifice

These critical orifices do not come calibrated. For factory calibration before your first use, please add PN-773 --- Calibration of Critical Orifice into your cart before checking out (for online/website order) or please contact our Regional Sales Office (for offline order).

A calibration certificate will be issued:

  • The critical orifices are calibrated according to US EPA Method 5 (US CFR Title 40, Part 60, Appendix A, Test Method 5) Section 16.2.2, using a dry gas meter calibrated according to US EPA Method 5, Section 10.3, and other reference instruments with calibrations traceable to the International System of Units (SI).

Aer Sampling recommends calibrating critical orifices at least once a year.

Aer Sampling's critical orifices shall only be calibrated in vacuum mode (i.e., critical orifice be upstream of the vacuum pump). Results from calibration in non-vacuum modes (i.e., critical orifice is downstream of the pump; pump is pushing gas into the critical orifice) are not comparable. Critical orifice must reach critical conditions to be usable.

Manufacturing Warranty and Technical Support


All our products come with a one-year warranty against manufacturing defects and one-month technical support for free. Please refer to our Frequently Asked Questions (FAQs) page for more details.


Information presented here is subjected to Aer Sampling Group's terms and conditions.
In case of discrepancy between English version and the non-English version, the English version shall prevail.
Doc ID: AERHQWW-k-150-en
Last revised (Excluding prices): 1; 08.22.22
Obsolete Catalog ID: PN-324, UC-OK



Bill of Materials (BOM)

What does this product contain? (r2):

The following items are included. Click the Catalog ID below to view individual components of this product.

S/N Catalog ID Quantity Item Name
1 PN-738 1x
Critical Orifice Assembly, Size 400 [EACH]
2 PN-739 1x
Critical Orifice Assembly, Size 480 [EACH]
3 PN-740 1x
Critical Orifice Assembly, Size 550 [EACH]
4 PN-741 1x
Critical Orifice Assembly, Size 630 [EACH]
5 PN-742 1x
Critical Orifice Assembly, Size 730 [EACH]
6 PN-285 1x Box, Critical Orifice, Assembly [EACH]


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