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Stack Sampling System Design

Stainless Steel Probes, Nozzles, & Flanges

Complete Stack Sampling Systems
  • Real-Time Monitoring
  • Sample Collection for Analysis
  • Mass Flow Control
  • Iso-Kinetic Sampling Systems
  • Custom Design
Stainless Stack Sampling Components
  • Shrouded Probes
  • Single Point Probes
  • Multi Point Particulate Probes
  • Multi Point Gas Sampling Probes
  • Slotted Sampling Probes
  • Flanges
  • Transport Lines
  • Precision Machined Nozzle Tips
Stack Sampling Design Standards
  • ANSI N13.1 1999
  • ANSI N13.1 1969
  • EPA
HI-Q is ready to help with your stack sampling requirements:

State and Federal nuclear regulatory agencies require a stack discharge sampling program as part of the licensing process. Radionuclides discharged to the air in the form of particulate and volatile compounds must be assayed. Therefore, nuclear facilities are required to follow standard protocol for sampling their effluent. Possible emission of radionuclides to the general public has to be monitored in a systematic and acceptable manner. In the United States, the Unites States Environmental Protection Agency (USEPA) has the authority over such matters, and the current requirements and guidelines for sampling in nuclear stacks and ducts are laid down in ANSI N13.1 1999.

The sampling requirements are such that a system has to be designed for the collection of 10µm aerodynamic diameter (AD) particles. This size has been chosen, keeping in view that any effect of an emission on the public's health, is restricted to the respirable mass it contained. Sampling of an effluent for gases, poses fewer problems compared to that of particulate. Therefore a system capable of successfully sampling 10µm AD particles will also be sufficient for sampling effluent gases.

In particle sampling, the challenges are many fold: 1) to aspirate particles from the stack flow into a sampling probe without bias, 2) to deliver those particles at the probe exit without any appreciable loss on the inner surfaces of the probe, 3) to further carry the particles through a transport line to a detection and analysis station without incurring additional losses and 4) to successfully analyze the sample and fulfill requirements, such as, raising an alarm (if needed) and/or to keep inventory of the release. According to the ANSI N13.1 1999 standard, the particle concentration at the detection/analysis station has to be at least 50% of that in the free stream.

HI-Q Environmental Products Company considers that the sampling probe is at the heart of the whole sampling system and is a very important design component. The sampling can either be done at multiple points at the sampling location with a rake of un-shrouded, sharp-edged, probes operated isokinetically or at a single point with a shrouded probe operated either non-isokinetically or isokinetically. The probe performance is the criterion to decide which type of sampling has to be used. For single-point sampling it has to be ensured that the uniformity of particle concentration has reached an acceptable limit at the sampling location, and that the correct type of shrouded probe is being used. For multiple-point sampling, the system has to be carefully evaluated to find out if it can achieve the acceptable performance as mentioned in ANSI N13.1 1999. The sample transport line has to meet the ANSI requirements as well. 

The following is a brief description of common stack sampling components:
Flanges Corrosion resistant stainless steel flanges or bulkhead plates are available for round or rectangular stacks, vents, or ducts.
Probes & Nozzles The probe can be single point, slotted, multiple point gas, or multipoint particulate depending on the size and configuration of the stack, vent, or duct.
Stack Flow We have a complete line of air velocity gauges and monitoring devices available to meet your needs. From multi-point pitot tubes to thermal anemometer systems.
Sample Flow A range of systems can be used, from a simple venturi flow meter with a manual control valve to mass flow measuring and control systems with digital displays for instantaneous flow rate and accumulated total.
Pump Systems Many standard systems are found throughout our catalog but special designed systems are available for stack/fume hood sampling as well. Multi-sampling-point tank systems and dual, flip-flop pump systems are available.
Instrument Weather Houses Our instrument weather houses are designed to house pumps and instruments in an outdoor area. They are the industry standard and have proved to be very durable with their baked on polyurethane painted finish. Nema rated enclosures are also available.