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Leak Procedure

Leak Testing Procedure Resources

A good leak survey starts with some established key essentials:

  • Training - ensure ultrasonic inspectors are at least Level 1 Certified
  • Equipment - use quality instruments capable of both mid and long distance detection. Be sure your ultrasonic detector will work well in high noise environments.
  • Tags - use a tagging system that will ensure leaks can be located by repair crews.  A tagging system must have accountability built-in

MB Hydro - Power Smart Profiles

1. Equipment Set-up  

Detecting High Pressure Ammonia Leaks with Parabolic Dish

Select the airborne ultrasound sensor to best suit the inspection.
  • Internal Sensor - perfect for pinpointing leaks within 15' range. Use precision indicators to shield parasite ultrasounds.
  • Flexible sensor - ideal for accessing tight spots and hard-to-reach areas. Bends and twists to reach behind piping and inside instrumentation panels
  • Extended Distance sensor - Designed to locate leaks up to 100'.  Perfect for ceiling pipes and dry pressurized sprinkler systems.
  • Parabolic sensor - Laser sighting allows surveyors to pinpoint within a very tight radius to location of overhead ceiling pipe leaks. Range extends to 200' and more (depending on the configuration of the leak.

Internal Sensor on Ultrawave 170 All SDT 170 ultrasonic detectors are equipped with an internal airborne sensor for detection of pressure and vacuum leaks.  This sensor is ideal for day to day leak detection where the source of the leak is within reach of the inspector.  Use in conjunction with the precision indicator kit (shown in Fig 1) to pinpoint the exact source of leakage.
Flexible Sensor - 21" or 36"

For inspections in hard to reach areas, choose the Flexible sensor available in 21 and 36 lengths.  It can be bent, twisted and shaped to go into any area that is inaccessible by hand.


EDS Extended Distance

Overhead piping in ceilings are prone to leakage but normally inaccessible without a ladder or scissor lift.  Inspection is now possible with the EDS Extended Distance Sensor.  The unique taper-shape funnels medium distance ultrasonic waves (50 100) onto the internal sensor of the SDT 170 providing the inspector with extended distance sensing and extreme directionality.


Parabolic Dish with Laser Sight

Select the parabolic sensor if the leaks you are detecting are outside the range of the EDS (Fig 3).  The parabolic shape focuses faint ultrasonic waves onto a super sensitive ultrasonic crystal amplifying and thereby extending the detection range by up to 250.  The laser sight pinpoints the exact source of the leakage, or use the rifle sight in bright daylight.


2. Operation   Functional Diagram of the SDT 170

Attach the sensor that was chosen for the inspection to sensor input on SDT 170. (Number 12)

Attach headphones to audio output of 170. (Number 10)

Switch SDT 170 equipment on. (Number 6)

Using "UP" and "DOWN" arrows on keypad, set amplification level (A=x) to a level that is comfortable for listening.


  1. Internal Sensor
  2. LCD Screen
  3. Blue Composite Protector
  4. Key Pad
  5. Back Light
  6. On/Off Switch
  7. Shoulder Strap Anchor
  8. Battery Charger Input
  9. RS232 I/O Connection
  10. Headphone Output
  11. Protector Cap, Sensor
  12. External Sensor Input

Typical LCD screen of Ultrawave 170M or 170MD


Ensure that the sensor is correctly connected to SDT 170 by identifying the sensor in the top left corner of LCD screen (LCD screen above indicates the "Internal Sensor" is active).   

Ensure battery charge is sufficient to take measurements by viewing icon in top right hand corner of LCD screen (Battery Load Icon)

After ensuring all safety procedures for your facility have been followed, proceed to the required inspection method described on next page.

3. Method for Leak Testing

Using the 21" Flexible to identify leakage in compressor line feed

  1. Set sensitivity using the up or down arrows to adjust the 170 to the environment you will be working in.

  2. With the amplitude as high as allowable for that environment, scan with an up and down, back and forth motion.

  3. Scan the possible leak area for a hissing sound. Listen and watch the signal. I

  4. f hissing sound is too loud, decrease the sensitivity of the SDT 170 by pressing the down arrow to a comfortable level.

  5. If a hissing sound is heard, get closer to the source of the hissing sound. Press the down arrow to decrease amplitude sensitivity as you get closer if hissing sound gets too loud.

  6. When you are near the leak, you may attach the localization probe to pinpoint the source of the leak. Scan back and forth, up and down, to confirm. Watch the SDT screen increase or decrease in signal as you scan.  Listen to the sound get louder and fainter as you scan. The spot where the sound is loudest is the leak site.

  7. Mark the leak source and repair on spot or tag for later repair.

  8. Document leak information (location, type of leak, size of leak, inspector, etc...).

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