NDI magnetic particle inspection consists of the establishment of a suitable magnetic field, application of magnetic particles, and examination and evaluation of the particle accumulation. The fluid consists of a mixture of fluorescent –coated magnetic particles and light petroleum distillate. Over time, the magnetic particles lose their fluorescent coating and the fluid accumulates debris from the inspected parts. Filtration systems operate by placing the inlet and outlet hoses into the site’s magnetic particle fluid holding tank. The fluid is drawn into the unit, passes through a coarse strainer and flows through the filter, which contains a combination of virgin wool and cedar chips. The filter medial removes particulates, moisture residue, and acidity form the fluid. The fluid is then circulated through the system several times until the desired fluid clarity is achieved. Degraded fluid is discarded as a hazardous waste and replaced with new fluid. All labs are required to change and replenish their fluid every 30 days in accordance with the maintenance requirement card (MRC). The filtered oil bath is clean and reusable with no detectable traces of stripped fluorescents, and greatly reduces the amount of hazardous waste generated during magnetic particle NDI operations. The NASNI NDI laboratory typically drains and disposes of around ten gallons of fluid each month. This technology is currently being used by Navy personnel involved in aircraft parts maintenance, shipboard parts maintenance, support equipment parts maintenance, and facility parts maintenance.

The compliance benefits listed here are only meant to be used as a general guideline and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g. the amount of workload involved.

• Reduced procurement costs for new fluid
• Reduced hazardous waste disposal costs
• Reduced amount of labor involved with maintaining magnetic particle fluid
• Reduced amount of downtime caused by maintaining and reordering magnetic particle fluid.
• Reduced worker exposure to hazardous materials.
• Conservation of natural resources

Aids in meeting pollution prevention goals

• 10 gallons of fluid replaced per month
• 120 Gallons of fluid replaced per year
• Cost of new fluid per gallon: $11.60

Labor

• Time required to drain fluid per month, hours: 0.25
• Time required to contain, label, complete, turn in/reorder documents and transport used fluid per month, hours: 0.75
• Total time required to change out fluid per month hours: 1
• Total time required to chance-out fluid per year, hours: 12
• Average NDI personnel pay grade (E-5): $ 18.41

Waste Disposal

• Gallons of fluid disposed per month: 10
• Gallons of fluid disposed per year: 12
• Weight per gallon, pounds: 10
• Total pounds of fluid disposed per year: 1200
• Hazardous waste disposal cost per pound: $2.25

Total Annual Costs

Consumables	$1,392.00
Labor	$220.92
Waste Disposal	$2,688.00
Total	$4,300.92

Consumables

• Filters replaced per year: 1.5
• Cost of new filter $100

Labor

• Time required to filter fluid per month, hours: 0.25
• Time required to contain, label, complete turn-in/reorder paperwork, and transport used filter per month, hours: 0.1
• Total time required to operate filtration unit per month, hours: 0.35
• Total time required to operate filtration unit pre year, hours: 1.2
• Average NDI personnel pay grad (E-5): $ 18.41
• Total NDI labor costs per year: $ 77.32

Waste Disposal

• Number of filters dispose of per year: 1.5
• Weight per filter, pound: 5
• Total pounds of filters disposed per year: 7.5
• Hazardous waste disposal cost per pound: $2.24

Total Annual Costs

Consumables	$150.00
Labor	$ 77.32
Waste Disposal	$ 16.80
Total	$244.12

Cost Analysis Summary (Per Year)

Annual Operating Costs
	Drain, Dispose and Replace Method	$4,300.92
	Magnetic Particle Purifier Method	$ 244.12
	Operating Cost change per Year	$4,056.80
Initial Procurement
	Magnetic Particle Fluid Purifier	$2,566.00
Expected Service Life		10 years
Return of Investment (per 10-year period)		$38,002
Break Even		0.63 years

NOTES:

1. A small quantity of "make-up " fluid may need to be replaced after filtration because some fluid adheres to parts that are removed from the fluid bath after inspection.

2. The cost analysis does not reflect the downtime due to the late delivery of replacement fluid. In the past, late deliveries have caused as much as three weeks of downtime.

3. NASNI replaced on filter after eight months: therefore, the system requires 1.5 filters per year.

4. It takes approximately 45 minutes (0.75 hours) to contain, label, complete turn-in reorder paperwork and transport a used filter. 1.5 filters require replacement per year (see note 3). Therefore, a year of filter change-outs adds approximately 6 minutes of labor to each month.

Mr. Dave Park
Phone: (732) 323-7128
DSN: 624-7128

This is not meant to be a complete list, as there may be other suppliers of this type of equipment.