FSLT Calibrated Helium Leaks


The FSLT Helium Leak Standards have been developed specifically to calibrate sniffer leak detectors and to avoid the clogging problems common to Calibrators that have a capillary leak element. This is particularly important for small leak rates and industrial plant use.

The FSLT Accu-Flow™ Calibrated Leaks are available for any specific leak rate within the usual range for “Sniffing” of 10-4 to 10-6 atm-cc/sec. They can be used with all makes of leak detectors.

Additional Information

Why choose the FSLT Calibrator?

WILL NOT CLOG OR BREAK – permeation leak element
FIXED LEAK RATE – for simple operation
SPECIFY EXACT LEAK RATES – your test point
WIDE LEAK-RATE CHOICE – the full range that is used for sniffing
EASY PROBE LOCATION – for repeatable results
SUITABLE FOR SF6 and OTHER GASES – call for more information
MEETS ISO REQUIREMENTS – NIST-traceable, A2LA-accredited Calibration Certification

Using the Calibrator

To calibrate a Helium Sniffer Leak Detector, the operator places the tip of the sniffer probe briefly into the tapered recess at the point source of gas flow of the FSLT. The leak-rate reading of the Detector is then adjusted to the Leak Rate of the Calibrator, as provided by VTI on the Calibration Tag. A second reading is obtained in the same way to assure the calibration of the detector.

You should compare the FSLT periodically to another Calibrated Leak if available, and return it to VTI for recalibration in accordance with your Quality Assurance/ISO schedule requirements.

Ordering Information

The FSLT Calibrators can be ordered for a single specified Helium leak rate within a wide range of values. When ordering or requesting a quotation, please provide the Part Number and also specify the Leak Rate requested using the full description of both the rate and the leak-rate units that you are requesting (for example: 2.0×10-4 atm-cc/sec). Also, please specify the manufacturing variance (“tolerance”) that you can allow on that Leak Rate as +/- 40%. or +/- 15%. The usual manufacturing variance is +/- 40% of the requested rate. (For the example rate above, the allowable range as manufactured would be from 1.2 to 2.8×10-4.) A “Special Range” variance is available of +/- 15%. (For the example, this would allow the leak rate, as delivered, to be from 1.7 to 2.3×10-4.) For this special manufacturing variance, an “-SR” is added to the end of the Part Number and there is an addition of $200 to the price of the Leak.

Please contact us for assistance if you have any technical or ordering questions or want a customized Leak or manufacturing variance. Other leak-rates units, such as Torr-liters/sec, can be specified and calibration data will be reported in the units requested.

Part Number Build-Up

The FSLT Series Part Numbers are constructed as follows:


where X = the code for the Leak Rate Range required,

where YYYYY = the code for the size of reservoir required. The X and Y codes are listed in the table below

As noted above, a -SR is added to the end of the part number to identify the special manufacturing variance of +/- 15% in the Leak Rate instead of the standard +/- 40% variance.

The FSLT model is identified as a Fixed-rate Calibrated Leak with a Teflon-permeation leak element and is specifically designed for calibrating sniffer type leak detectors. The “He” in the part number identifies this as a Helium Calibrated Leak and the “WFV” designates the particular Teflon-packed stainless steel fill valve used on the product.

Order Codes

X Code: For Leak Rates from:
4 1.0 to 9.9×10-4 atm-cc/sec
5 1.0 to 9.9×10-5 atm-cc/sec
6 1.0 to 9.9×10-6 atm-cc/sec
Y Code: For Reservoir Size:
150DOT 150cc
300DOT 300cc
500DOT 500cc
1000DOT 1000cc

Leak Rate Ranges Available and Example Part Numbers

Examples of Common Part Numbers: For a Specified Value in this Range: Reservoir Size:
FSLT-4-HE-1000DOT-WFV  1.0 to 9.9×10-4 atm-cc/sec 1000cc 
FSLT-4-HE-500DOT-WFV  1.0 to 3.0×10-4 atm-cc/sec 500cc 
FSLT-5-HE-500DOT-WFV  1.0 to 9.9×10-5 atm-cc/sec 500cc 
FSLT-5-HE-300DOT-WFV  1.0 to 9.9×10-5 atm-cc/sec 300cc 
FSLT-5-HE-150DOT-WFV  1.0 to 3.0×10-5 atm-cc/sec 150cc 
FSLT-6-HE-150DOT-WFV  1.0 to 9.9×10-6 atm-cc/sec 150cc 
FSLT-6-HE-300DOT-WFV  1.0 to 9.9×10-6 atm-cc/sec 300cc