Sub-slab Soil Gas Sampling System with Barbed Adaptor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for collecting sub-slab soil gas samples are cumbersome, prone to leaks, and invasive, requiring multiple installations and causing damage to slabs, with limitations in sampling at varying depths and risk of clogging or contamination.
Innovation Solution
A device system with a machined adaptor body and extensions, featuring barbed and filter components, allows for air-tight installation and removal through a one-inch diameter hole, enabling sampling at varying depths without clogging or contamination, using a standard coring machine and hammer for installation, and adaptable for different VOC measuring devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vapor points with threaded fittings are used for sub-slab sampling, then sampling can be performed, but leaks occur at fittings and along the vapor point edge allowing indoor air to dilute the sample
Solution Approach 1:
The vapor point assembly is divided into separate components: a removable cap, a sampling port, and a barrier member that can be independently positioned. This segmentation allows each component to be optimized for its specific function while maintaining overall system integrity and preventing leaks.
Solution Approach 2:
A barrier member is introduced as an intermediary element between the sub-slab environment and the sampling system. This barrier member prevents indoor air from reaching the sampling interface while allowing vapor extraction, thereby eliminating the leakage pathway without compromising sample integrity.
2Productivity
If vapor points are disconnected and reconnected for multiple sampling occasions, then repeated sampling is enabled, but fittings progressively loosen and leak more readily
Solution Approach 1:
The system employs a dynamic sealing mechanism where the barrier member can be repositioned and the cap removed/reattached without compromising the seal. This dynamic design enables repeated sampling operations while maintaining consistent sealing performance across multiple uses.
Solution Approach 2:
The barrier member is pre-positioned to create a seal before sampling begins, and the cap is designed to maintain this seal during repeated attachment and detachment cycles. This prior cushioning prevents progressive loosening by distributing mechanical stress away from the fitting threads.
3Reliability
If cement is used to anchor the vapor point to ensure air-tightness, then sealing is improved, but the cement must cure requiring a waiting period before sampling
Solution Approach 1:
The curing requirement is extracted from the sealing function by replacing cement-based anchoring with a mechanical sealing system using the barrier member and cap. This extraction eliminates the time delay associated with cement curing while maintaining air-tight seal integrity through the removable cap mechanism.
4Ease of operation
If drilling and coring methods are used to install vapor points, then access to sub-slab gas is achieved, but damage to the slab and inconvenience to occupants occur
Solution Approach 1:
The system uses a flexible barrier member that can be inserted through a minimal opening in the slab without requiring extensive drilling or coring. This flexible component conforms to the slab surface and creates an effective seal with minimal intrusion, thereby reducing slab damage while maintaining installation capability.
Data Source
AI summary
A system for sampling sub-slab soil gas having an adaptor body that includes a first barbed portion, a collar portion, a second barbed portion, an internal cavity that axially passes through the length of the adaptor body, and a coupling portion. The system further includes one or more extensions such as a fitting extension, a filter extension, a sieve extension and a length extension, each of which are threadably retainable with the coupling portion of the adaptor body.