An additional aspect of design is the inspection of surface roughness/finish and welding. Rough surface textures increase friction on components in contact with each other and are more prone to excessive wear. Welding poses much of the same risk if burrs, improper polishing, and poor technique are present.
Often overlooked is the level of clearance in and around equipment, particularly in the product zones. Full access to equipment while performing preventative maintenance tasks to ensure proper function is important to eliminate premature failure or breakage. Providing adequate distance allows employees to inspect equipment throughout production operations for integrity, alignment, and setup.
Understanding overall foreign material risk requires both an analysis of the process environment and of the equipment itself. Characteristics of the process environment to consider when determining foreign material risk include, but are not limited to, product exposure status or zones, location of equipment on the production line, detection methods throughout the production line, and frequency of equipment inspection.
The concept of zones is of particular importance as it pertains to exposure of the product to components in the equipment. Product zones where direct contamination can occur are inherently higher risk than non-product zones on equipment or facility infrastructure. Risk management efforts are thus first focused on higher risk product zones.
The location of a selected piece of equipment within the production line also determines the level of risk associated with the process. The amount or volume of product that could potentially be affected if a foreign material incident occurs should be taken into consideration. Upstream grinding operations that feed numerous lines are higher risk than a single line where product is already formed or packaged, see Table 1.
The type and quantity of detection methods present throughout the production line can impact overall risk. Methods such as X-ray are able to detect a wider scope of materials than a simple metal detector or visual inspection and would lower total process risk. Having multiple devices, such as X-rays, spread out over the process would also lower risk.
Similar analysis could be applied to the frequency of equipment inspections performed during operations. Equipment that is continuously inspected for integrity present lower process risk than those items only inspected prior to startup.
Equipment Design Characteristics
As when assessing risks associated with certain process characteristics, a similar structure can be used when analyzing sanitary design for foreign material. Examples pertaining to metal selection in a chemically cleaned environment are demonstrated in Table 2.
Other sanitary design specifications as defined by various industry organizations can also be placed on a spectrum of risk for further analysis.
Quantifying Overall Foreign Material Risk
Once an assessment of all the various risk factors has been undertaken, numerically quantifying given risk can be helpful to determine priority of corrective actions and preventative measures.
A simple method to numerical rank risk is using a 1-10 scale, where a high-risk item or characteristic would be assigned a number 10 and lower risk items or characteristics would be assigned a lower number.
The example process risk factors described earlier could then be assigned a number in a table, after which the average of process risk can be computed, see Table 3.
Adding the process risk rating with the assigned sanitary design risk rating would give a total overall sum of risk.
Equipment and associated components can pose a risk for foreign material through various physical means. Understanding sanitary design factors allows for the ability to assess and quantify risk and subsequent actions needed to bring the system into appropriate control.