If You Can’t See It, You Can’t Clean It: Minimizing Voids and Niches in Sanitary Design

In last October’s issue of From Experience, we examined two principles of sanitary design: establishing hygienic zones based on product-exposure risk and controlling personnel, material, and waste flows. Those principles address facility layout and movement: This article turns to the construction details that make a facility cleanable.

Principle 9 of the Facility Sanitary Design Checklist calls for building components and construction details that support sanitary conditions by minimizing harborage points, sealing joints, and avoiding voids. Voids are concealed spaces where moisture or contaminants can accumulate, while niches are areas that are difficult to inspect and clean. Both can support microbial growth and allow hazards to persist unnoticed, undermining an otherwise well-designed sanitation program.

These conditions are not always obvious: Structural members, wall systems, platforms, and later modifications can create them unintentionally. The following examples show how common design and construction decisions can either create or help minimize sanitary design risks.

• Structure. Structural columns show how one design decision can either eliminate or create hidden risk. In new construction facilities, keep structural members outside hygienic processing spaces whenever feasible. When a column must remain in the room, use an open structural section, such as a wide-flange column. Open sections avoid enclosed cavities and improve visibility, access, drainage, and cleanability. Treat wrapped or enclosed columns as managed-risk conditions rather than preferred solutions.

Existing facilities often require a different approach. Painted steel columns may not withstand repeated washdown or aggressive sanitation chemicals. Enclosing a column can improve surface durability and cleanability, but it creates a concealed cavity. When an enclosure is unavoidable, reduce and manage the resulting risk through appropriate protective treatment of concealed surfaces, sealed interfaces, documented inspection, and timely repair.

• Materials of Construction. Sanitary performance depends on the complete assembly, not just the individual material. Concrete Masonry Units (CMUs) have joints, textured surfaces, and internal cavities that require careful detailing and protection. Insulated Metal Panels (IMP) and coated precast or tilt-up concrete can provide smoother, less porous surfaces, but their performance still depends on sound joints, sealed penetrations, coating integrity, drainage design, installation quality, and maintenance.

• Platforms.  The same principles apply to platforms and support systems in hygienic processing spaces. Platforms, stairs, handrails, and guardrails can create sanitary risks when fabricated from hollow members. If hollow sections are not continuously sealed and protected from later penetrations, water can enter spaces that cannot be inspected or sanitized. Where practical, use open structural sections, such as wide-flange members, angles, channels, and plates, to improve visibility, access, drainage, and cleanability.

• Modifications and Maintenance. Post-construction modifications can compromise otherwise well-detailed construction. Mounting a sign, installing a bracket, or adding a pipe support may create an opening into a previously sealed assembly. Require sanitary review for every attachment and penetration, use approved sealing details, include them in routine inspections, document deficiencies, and repair failures promptly. Without these controls, moisture can migrate into hollow members, wall assemblies, and concealed components while exterior surfaces still appear acceptable.

Note that the above examples are representative, not exhaustive: Similar risks occur wherever details limit visibility, access, drainage, or cleanability. The following guide presents four approaches for addressing voids and niches: avoid creating them, manage unavoidable conditions, improve existing details, and eliminate hazards where feasible.

Decision Guide for Managing Voids and Niches

Avoid

• Creating inaccessible enclosures or unsealed hollow sections.
• Specifying porous or difficult-to-clean finishes in hygienic spaces.
• Adding penetrations without sanitary review and sealing.
• Creating horizontal ledges, undrainable surfaces, or concealed joints.

Manage

• Enclose existing structures only when renovation constraints make concealment unavoidable.
• Seal all penetrations and enclosure interfaces against water intrusion.
• Inspect sanitary barriers routinely and repair deficiencies promptly.

Improve

• Modify structural elements that must remain to improve visibility, access, drainage, and cleaning.
• Upgrade seals, coatings, and inspection provisions.
• Reduce penetrations and attachments to the practical minimum.

Eliminate

• Locate structural members outside hygienic processing spaces.
• Replace hollow members with open structural sections.
• Remove inaccessible cavities and unnecessary enclosures.

The sanitary design objective is straightforward: Eliminate hidden spaces wherever feasible and actively control those that cannot be eliminated. Apply four questions to every surface, connection, support, and post-construction modification:

• Can it be seen?
• Can it be reached?
• Can it drain?
• Can it be cleaned and maintained to the required standard?

If any answer is no, reconsider the detail or establish a documented control strategy. Hidden spaces create hidden risks. Effective sanitary design makes those risks visible, accessible, and manageable.