SOA Deep Cleaning Extractors and Systems Provide Superior Results
Careful Measurement Leads to Superior Performance
The CRI Seal of Approval program tests the effectiveness of deep cleaning extractors and systems. To qualify for the Seal, extractors must meet stringent standards in all three test categories:
- Soil removal — CRI uses NASA-enhanced x-ray fluorescence technology to measure the precise amount of soil removed from the carpet, and soil removal efficiency is rated on four levels. Extractors that exceed average soil removal levels receive a Bronze Seal rating. Those achieving higher levels of soil removal receive a Silver or Gold rating. Extractors that remove the highest level of soil earn the CRI Platinum Seal of Approval.
- Water removal — The extractor or system must remove most of the moisture resulting from a wet cleaning process. Dirty water that remains in the carpet could be a source of fungal growth and could prolong the drying process.
- Texture retention — The extractor must not harm the carpet pile.
If a system is being tested, additional test criteria are included and mirror those from the Cleaning Solutions protocol. These include the following:
- Rate of resoiling — This ensures that the product does not attract dirt to the cleaned areas faster than the rest of the carpet.
- pH — A more neutral pH ensures that carpet dyes and fibers are not adversely affected.
- Optical brighteners — None are allowed, as they can leave some patches of carpet lighter than the rest.
- Colorfastness — Products must not be so aggressive that they cause a color change in the carpet.
Additional Technical Testing Information
Testing for soil removal: To test for soil removal performance, the independent laboratory uses a “designer” soil that has properties similar to soil found in carpet across the United States. A significant new element to this testing protocol is the use of x-ray fluorescence (XRF) technology, which was developed by private industry and enhanced by NASA for the Space Shuttle program. XRF enables the laboratory to identify and quantify the various compounds found in the soil. Using the XRF analyzer, laboratory staff measure the starting concentration of each compound applied to the carpet sample (following ASTM protocols) and, following cleaning with an extractor, quantify the precise amount of soil removed.
Testing for residual water: To measure how well an extractor recovers water, the test carpet sample is weighed before and after the standardized process to determine how much water remains.
Testing for texture retention: Finally, surface appearance change in the carpet pile, as a result of extraction cleaning, is measured using CRI’s Texture Appearance Retention Reference Grading Scales, which provide a visual aid in assessing appearance change in carpet.
- X-Ray Fluorescence and Cleaner Carpet: Learn how x-ray fluorescence was adapted for space flight and carpet cleaning.
- See the XRF Test in action!
Deep Cleaning Extractor and System Testing Criteria
Deep Cleaning Extractors Testing Criteria
To qualify for Seal of Approval, extractors must meet testing requirements for three important elements of performance. Each of these tests is explained in the brief overviews below:
1. Standard Test Practice to Evaluate Cleaning Effectiveness of Carpet Cleaning Equipment Using X-Ray Fluorescence
X-ray Fluorescence (XRF) is used to detect elements of each compound used to soil a control carpet, then to determine their concentrations after a cleaning process. XRF is a technique that detects elements by ionizing the constituent atoms and recording the characteristic energy signatures given off by the elements as they seek to regain greater stability.
Five compounds containing suitable elements for XRF detection were chosen with consideration given to particle size (Fe3O4 at < 1 micron to ZnO at < 74 microns), hardness, solubility, and surface characteristics.
Each compound is first applied to nylon pellets at 6 grams of compound per 1000 grams of pellets (3g/1000 for strontium carbonate). Fifty grams of each of the five compound coated pellets are used to soil a 400 square-inch carpet following procedures found in ASTM-D 6540. Each soiled carpet is vacuumed with a straight suction air tool before it is scanned using XRF to verify the starting concentration of each compound. All XRF scans are with the carpet on a conveyor such that in the 3-minute scan approximately 120 square inches of the 400 square inch carpet are analyzed. The soiled test carpet is then cleaned with the extraction equipment submitted for evaluation. Two wet and two dry passes at 1.0 foot / second are applied unless otherwise specified. Three samples per test are used and the average result for amount removed is reported.
- Soil Removal Standard – Percent of soil removed after water only cleaning operation.
- 55 – 69% to obtain SOA Bronze Certification
- 70 – 79% to obtain SOA Silver Certification
- 80 – 89% to obtain SOA Gold Certification
- 90 – 100% to obtain SOA Platinum Certification
2. Standard Test Practice for Determining Residual Moisture as a Result of Water Extraction
This test practice is intended to determine the moisture left in a specific carpet as a result of simulated cleaning with a standard hot water extraction machine. The resultant difference in weight is measured and reported as ounces of residual moisture per square yard.
- Residual Moisture in carpet immediately after cleaning operation.
- ≤ 271 g/m2 (8 oz/yd2)
3. Standard Test Practice for Determining Surface Appearance Change as a Result of Wet Extraction
This test practice provides a laboratory test for the measurement of surface appearance change of textile floor covering as a direct result of multiple cleaning passes in a controlled environment.
This test practice is applicable to all residential/commercial cleaning systems. Six cleaning cycles are applied to residential cut pile carpet for residential specific systems. Eleven cleaning cycles are applied to commercial cut pile carpet for commercial specific systems. Texture appearance change is visually rated.
- Appearance Retention:
- No more change in the deterioration of the carpet pile surface than Standard CRI Photographic Reference Scale.
CRI Test Method 118 Laboratory Test Procedure for Seal of Approval Deep Cleaning Extractors.