UST Programs - LG 113

Issue Date: November 22, 1995
Revision Date: August 23, 1999

Tidel Engineering, Inc.

EMS-3500 Liquid Discriminatory Probes Part 301-0635, Containment Sump Probes Part 301-0642,
Tidel Detector #301-0752-001

INTERSTITIAL DETECTOR (LIQUID-PHASE)

Detector:

Output type:	qualitative
Sampling frequency:	continuous
Operating principle:	electrical conductivity/hydrocarbon sensitive polymer (Liquid Discriminatory Probes Part 301-0635), magnetic switch/float and hydrocarbon sensitive polymer (Containment Sump Probes Part 301-0642), float switch (Tidel Detector #301-0752-001)

Test Results:
*California requires annual certification of all leak detection equipment. The certification of discriminating sensors should include functional testing of both water and product detection capabilities.

Model 301-0635 and 301-0642: Currently the SWRCB UST Program staff discourages the use of polymer strip discriminating sensors at new installations in California. This is due to concerns about the impact that repeated/prolonged exposure to hydrocarbons may have on the sensor's ability to alarm and recover from alarm reliably. Since current evaluation protocols do not address this issue, no new polymer strip sensors should be installed until new evaluation protocols are in place.

	unleaded gasoline		water
Liquid Discriminatory Probes Part 301-0635
Response time (min)	3.59		0.96
Recovery time (min)	13.18		<1
Product activation height (cm)	1.76		0.49
Lower detection limit (cm)	4.19		1.52

			high*		low*
Containment Sump Probes Part 301-0642
Response time (min)	6.39		4.12		4.76
Recovery time (min)	>60		<1		<1
Product activation height (cm)	2.27		19.22		4.31
Lower detection limit (cm)	2.32		N/A**		4.31

	50% by weight ethylene glycol in water			30% by weight calcium chloride in water
Tidel Detector #301-0752-001	high	low	high		low
Response time (min)	21.91	30.10	22.27		31.08
Recovery time (min)	<1	<1	<1		<1
Product activation height (cm)	28.92	2.75	28.82		2.48

*The "high" and "low" refer to high and low level alarm points of hydrostatic sensors.
**See Glossary

Specificity Results (in addition to above for Liquid Discriminatory Probes Part 301-0635 and Containment Sump Probes Part 301-0642):
Activated: synthetic gasoline, diesel, heating oil #2.

Comments:
Liquid Discriminatory Probes Part 301-0635 and Tidel Detector #301-0752-001 are reusable.
Containment Sump Probes Part 301-0642 was tested to determine its capability of detecting hydrocarbons floating on water. A Lower detection limit thickness of 0.04 cm was declared, on average, in 16 minutes, 41 seconds with recovery time averaging 12 minutes, 55 seconds.
Tidel Detector #301-0752-001 is intended to monitor the level of either ethylene glycol or calcium chloride solutions in interstitial or annular space of a double-walled tank. Detector activates an alarm if any significant gain or loss of solution occurs.

Tidel Engineering, Inc.	Evaluator: Carnegie Mellon Research Institute
2310 McDaniel Dr.	Tel: (412) 268-3495
Carrollton, TX 75006	Dates of Evaluation: 01/29/93, 02/17/93 , 04/20/93
Tel: (800) 678-7577

Appearance on this list is not to be construed as an endorsement by any regulatory agency nor is it any guarantee of the performance of the method or equipment.
Equipment should be installed and operated in accordance with all applicable laws and regulations.
For full details, please refer to our expanded "DISCLAIMER" page.