FOD Sign Placement Guide

By FODBag.com · Updated November 9, 2026

FOD Sign Placement Playbook: Decision Points, a Three-Location Example and a Sightline Check

This playbook is for the EHS or facilities lead who has to put the right FOD sign at the right decision point, at a size people can actually read, without turning a loose sign into FOD. It sets out what public documents say about area signs and accident-prevention signs, works one hangar entrance, one aircraft bay and one tool crib through a placement plan, and gives a sightline audit you can walk. Every source is listed at the bottom with the paragraph or slide we read.

What the published sources say about signs

NASA requires signs at the entrances to FOD Awareness Areas, FOD Control Areas and FOD Critical Zones that clearly indicate the level of control (NASA MSFC-STD-3598 Rev. D, paragraph 5.5.7.1). Awareness signs and media shall also be posted to remind workers and visitors of the requirement for FOD prevention (5.5.7.2). The standard images (or equivalent) are a blue diamond for Awareness Areas, a yellow Yield sign for Control Areas and a bold red Stop sign for Critical Zones (5.5.7.3). NASA does not, in the paragraphs we read, set a mounting height, a sign size or a letter height.

IAQG’s public guidance says the organization should determine area designation from a FOD risk assessment and set controls for each designation, and that “FOD Prevention Area Designation signs communicate the level of risk and promote compliance.” It shows Awareness, Control and Critical as commonly used designations (IAQG SCMH 3.4.2 Rev. D, slides 21–22).

OSHA 29 CFR 1910.145 applies to the design, application and use of signs intended to indicate specific hazards; it covers all safety signs except those for streets, highways and railroads, and it does not apply to plant bulletin boards or safety posters ((a)(1), (b)). It classifies signs as danger, caution or safety-instruction ((c)(1)–(c)(3)). All signs shall have rounded or blunt corners, be free from sharp edges, burrs, splinters or other sharp projections, and have fasteners located so they do not constitute a hazard ((d)(1)). Danger signs use red, black and white; caution signs use a yellow background with a black panel; safety-instruction signs use a white background with a green panel ((d)(2), (d)(4), (d)(6); colors per ANSI Z535.1 tables incorporated in 1910.6). Wording “should be easily read and concise,” contain sufficient information to be easily understood, make a positive rather than negative suggestion, and be accurate in fact ((e)(2)).

What FODBag publishes about its FOD signs

The FOD signs category and the FOD Control Area sign product page, read on Nov. 9, 2026, offer signs in 11 in × 14 in, 16 in × 20 in and 20 in × 30 in, with published prices from $29.99 to $79.99. The Control Area sign is listed as 5 mm foam board, part number FODSign-ControlArea. FODBag uses blue for FOD Awareness Areas, yellow for Control Areas, red for Critical Areas and green for Safe Areas; FOD Safe Area is a local designation and should be defined in your written program if you use it. See FOD signs and FOD area signs.

Worked example (illustrative): one entrance, one bay and one tool crib

This is an illustrative example. The dimensions and distances are invented to show the method. Your risk assessment sets real decision points. The site is a hangar bay used as a FOD Control Area, with a nested FOD Critical Zone around a work stand, a 3 ft personnel door from a 40 ft corridor, two 20 ft roll-up doors from the apron, and a tool crib window in the corridor just outside the personnel door. Floor lines are already planned in the area classification guide; this example only places the signs.

1. Hangar personnel entrance (Control Area). One FOD Control Area sign on the latch-side wall, before the yellow floor line, so a person in the corridor sees it before they cross the threshold (NASA 5.5.7.1). Do not put it on the door leaf: when the door stands open the message disappears, and a sign on a swinging door is easier to hit. Approach along the corridor is about 40 ft; a 20 in × 30 in sign is the FODBag size offered for longer viewing. That size choice is a FODBag suggestion. Walk the last 15 ft and confirm the area name and the rule can be read at a normal walking pace (OSHA 1910.145(e)(2) on wording that is easily read and sufficient).
2. Aircraft bay (two apron doors plus the Critical Zone). One Control Area sign at each roll-up door, on the jamb or adjacent wall, readable from the apron before the threshold tape, not on the moving curtain. If the apron approach is longer than the corridor, use 20 in × 30 in again and walk it. At the Critical Zone entry to the work stand, one FOD Critical sign, close-range (a few steps), 11 in × 14 in or 16 in × 20 in, at the controlled access point, not inside the zone where it has to be walked around. NASA 5.5.7.1 and 5.5.7.3.
3. Tool crib window. The crib is a decision point for tool issue, not an area entrance by itself. One tool-accountability sign faces the queue at the window, 16 in × 20 in as a general-use size, mounted so a person standing in line can read it without leaning through the opening. If the corridor is already signed as Control at the hangar door, do not add a second Control Area sign on the same wall; one message at each decision point is enough.

Sign count for this example: three Control Area signs + one Critical sign + one tool-accountability sign = five signs. Floor lines still belong to FOD floor tape in 2 in × 108 ft rolls; the tape marks the boundary and the sign names it. Sizes above are chosen from the three sizes FODBag publishes, after walking the approach. They are not a letter-height calculation from ANSI Z535.2, which we have not read.

Sightline and mounting audit (walk the approach)

Walk each approach the way a new employee or a visitor would walk it. The checks are a FODBag suggestion assembled from the paragraphs cited; add your own site rules.

• Every entrance to a FOD Awareness Area, Control Area or Critical Zone has a sign that states the level of control (NASA 5.5.7.1).
• The message is readable at the decision point, before the person crosses the tape or reaches the window (OSHA 1910.145(e)(2)). If it is not, move the sign or choose a larger size from the sizes you have approved; do not add a second competing sign on the same wall.
• The sightline is clear: an open door, a parked cart, a stack of bins or an aircraft tail does not hide the sign from the approach.
• The sign is not on a moving door leaf or roll-up curtain unless your procedure specifically allows it and the message remains visible when the door is open.
• Corners are rounded or blunt, edges are free of burrs, and fasteners do not stick out as a hazard (OSHA 1910.145(d)(1)). A foam-board sign is secured so it cannot fall; a loose sign is FOD and a struck-by hazard.
• Wording is short, accurate and consistent with the written program and with any sticker or tape colors in the same area (1910.145(e)(2)). For message drafting, use the wording guide.
• OSHA danger or caution signs, if present for other hazards, are not visually mixed with FOD area symbols on the same panel. If both systems are in use, the written program says how they relate.
• After a layout change, repeat the walk. An outdated sign trains people to ignore signs.

Where to go next

Once the decision points are mapped, choose signs from FOD signs (from $29.99) and FOD area signs, and keep the floor line consistent with FOD tape in 2 in × 108 ft rolls. Questions about matching a sign to an entrance or a viewing distance? Call FODBag at 602-874-1313.

Sources and how we used them

1. NASA MSFC-STD-3598 Rev. D, Standard for FOD Prevention (effective July 26, 2021) — Paragraphs 5.5.7.1, 5.5.7.2 and 5.5.7.3 (entrance signs, awareness media, and the blue diamond / yellow Yield / red Stop symbols). The paragraphs we read do not set size or mounting height. Free public PDF, read in full. Accessed Nov. 9, 2026.
2. IAQG SCMH 3.4.2 Rev. D, FOD Prevention Program: Guidance in Support of IAQG Standard 9146 (June 19, 2023) — Slides 21–22: area designation from a FOD risk assessment; area-designation signs communicate the level of risk; commonly used designations. Slide numbers are the footer numbers in the PDF. Free public document. Accessed Nov. 9, 2026.
3. OSHA 29 CFR 1910.145, Specifications for accident prevention signs and tags — Section 1910.145 read in full on the OSHA page and on eCFR, Nov. 9, 2026: (a)(1)–(a)(2), (b), (c)(1)–(c)(3), (d)(1), (d)(2), (d)(4), (d)(6), (e)(2), and (f)(4)(ii) (the five-foot rule for tags). osha.gov often returns 403 to automated fetches; the text was read via WebFetch.

ANSI Z535.2 and Z535.4 are paid and were not read; no clause numbers or letter-height ratios from them are cited. OSHA cites ANSI Z535.1-2006(R2011) only for color-sample tables via 1910.6. AS9146 and NAS 412 are paid and are not quoted here. FAA AC 150/5210-24A was read and is not used as a hangar placement rule. FODBag product facts come from the signs category and the FOD Control Area sign product page, read Nov. 9, 2026. The example is illustrative and is not a customer case.

Get the Free Guide

Enter your details and we will email you the PDF of FOD Sign Placement Guide right away.