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Passive Fish-Friendly Screens (PSF)

Low-velocity intake protection where power isn't feasible and regulations apply.

PSF = Passive Screening & Fish Protection

PSF screens are fixed cylindrical strainers with 3/32" or smaller openings, designed to meet fish protection regulations without requiring power or moving parts. Large surface area maintains low approach velocity (typically ≤0.4 fps) to prevent fish impingement. Ideal for remote sites, gravity-fed systems, or anywhere electrical infrastructure is not feasible.

Why Choose PSF Passive Screens?

No Power Required

Zero moving parts, no electricity, no controls. Fixed cylindrical screen protects fish through proper sizing and low velocity. Ideal for off-grid and remote sites.

Fish-Friendly Design

Meets ≤0.4 fps approach velocity requirements. Large surface area prevents impingement. 3/32" or smaller openings. Agency-compliant for permit applications.

Robust Construction

304 stainless steel construction. Multiple diameters and lengths available. Bolt-on mounting for easy installation and removal. Withstands harsh environments.

System Integration

Works upstream of BIG or TIG inline filters for complete two-stage protection. PSF handles bulk debris, inline filter provides final polishing for emitters.

PSF Specifications & Flow Capacity

All models sized to meet ≤0.4 fps approach velocity with adequate submergence. Flow capacity in both GPM and CFS for hydraulic calculations.

SizeItem #GPMCFSConnectionScreen Dia (in)Screen Length (in)Stand-Off (in)
3"AA503751/63 NPTM68½12
4"AA5041501/34 NPTM811½16
5"AA5053002/35 FLG1017½20
6"AA5064440.996 FLG1123½22

Note: .062 perf is the smallest recommended perf screen size.

Fish Protection & Regulatory Compliance

Approach Velocity Compliance

PSF screens meet the ≤0.4 fps approach velocity standard required by most fish protection agencies. Large screen surface area distributes flow to maintain low velocity through openings, preventing fish impingement and allowing safe passage.

  • ≤0.4 fps standard (WDFW, NMFS, CDFW)
  • Calculated for site-specific conditions
  • Compliance documentation provided

Screen Opening Standards

PSF screens use 3/32" (0.094") perforations as standard, meeting fish exclusion requirements for most jurisdictions. Smaller openings (1/16" or 2mm) available for stricter regulations or sensitive species protection.

  • 3/32" standard (typical requirement)
  • 1/16" or 2mm for strict jurisdictions
  • Custom openings for special cases

Agency Coordination: CTC filtration specialists works directly with permitting authorities to ensure PSF screens meet all local, state, and federal requirements. We provide approach velocity calculations, compliance drawings, and technical documentation for your permit application. Agencies we regularly work with: WDFW, NOAA Fisheries (NMFS), CDFW, ODFW, USBR, USACE, and local irrigation districts.

Options & Accessories

Protective Hoops

External reinforcing rings around screen cylinder prevent damage from floating debris, ice, or impact. Recommended for 8" models, required for 10" and larger screens exposed to debris loading.

  • Protects screen mesh from damage
  • 304 SS construction
  • Maintains stand-off clearance

Anti-Vortex Features

Vortex suppression plates and end caps prevent air entrainment in shallow or turbulent water conditions. Critical for applications near water surface or in high-velocity flow zones.

  • Prevents air entrainment
  • Required for shallow submergence
  • Improves pump efficiency

Mounting Kits

Custom mounting hardware for bolt-on, flange, or threaded connections. Includes lifting brackets, anchor points, and hardware matched to your existing pipe or installation method.

  • Matches existing pipe OD or flange
  • Lifting eyes for installation/removal
  • Stainless hardware included

Custom Fabrication: Every PSF screen is custom-fabricated to your specifications. Provide pipe OD, flow rate, water source details, and jurisdictional requirements—we'll engineer a compliant solution. Special configurations available for challenging installations, extreme environments, or unique regulatory requirements.

Installation & Maintenance

Installation Guidelines

  • Position screen with adequate submergence (2× screen diameter minimum)
  • Orient perpendicular to flow when possible to minimize impingement
  • Maintain stand-off clearances per spec table
  • Secure mounting to prevent movement or rotation
  • Use lifting eyes for safe removal during maintenance

Maintenance Requirements

  • Inspect regularly during operating season (weekly to monthly)
  • Clean when debris accumulation visible or flow reduced
  • Remove and rinse with hose or brush exterior
  • Check for damage—repair or replace damaged screens
  • Heavy debris loading may require daily cleaning or SCS2 upgrade

Frequently Asked Questions

Ready to Protect Your Intake with Fish-Friendly Screening?

Our filtration specialist team will calculate approach velocities, design compliant PSF screens, and provide documentation for your permit application. Custom fabrication to meet local, state, and federal fish protection requirements.