Bollard Spacing Calculator

Inputs

Enter the protected run length and spacing preferences. For complex layouts, supply segment lengths.

Units

Total run length (m)

Left clearance (m)

Right clearance (m)

Openings lengths (m)

Comma-separated. Example: 3, 2

Edge offset inside segment (m)

Keeps bollards away from segment ends.

Spacing mode

Max spacing (m)

Used when mode is maximum spacing.

Fixed spacing (m)

Used when mode is fixed target spacing.

Safety factor

Greater than 1 reduces spacing conservatively.

Bollard diameter (m)

Used for constructability warnings.

Include end bollards per segment

If off, bollards are placed interior-only.

Advanced Layout

Optional: provide segment lengths to model separated runs (e.g., between gates). If provided, openings are not used to split segments.

Segment lengths (m)

Comma-separated. Example: 8, 10.5, 6

Gap between segments (m)

Adds a gap after each segment, except the last.

Example Data Table

Scenario	Total Run	Clearances	Openings	Mode	Spacing Limit	Edge Offset	Typical Outcome
Warehouse edge	30 m	0.5 m + 0.5 m	3 m, 2 m	Maximum	1.5 m	0.2 m	Computes minimum bollards meeting spacing limit.
Loading bay	18 m	0.3 m + 0.3 m	2.4 m	Fixed	1.2 m	0.15 m	Fits placement to target spacing conservatively.
Multi-run layout	25 m	0.5 m + 0.5 m	Not used	Maximum	1.6 m	0.25 m	Uses segments like 8, 10, 6 with gaps.

Formula Used

The calculator first determines the usable length available for bollards. If you do not provide segment lengths, it uses a single segment:

Effective Length = Total Length − Left Clearance − Right Clearance − Sum(Openings)
Usable Segment Length = Segment Length − 2 × Edge Offset
Effective Spacing Limit = Spacing Input ÷ Safety Factor

For each segment, bollards are placed to satisfy the spacing requirement.

If end bollards are included: n = ceil(Usable / Limit) + 1, Actual Spacing = Usable / (n − 1)
If end bollards are excluded (interior-only): n = ceil(Usable / Limit), Actual Spacing = Usable / n

How to Use This Calculator

Enter the total run length and choose meters or feet.
Add left and right clearances where bollards cannot be installed.
Enter opening lengths for gates or access gaps, if applicable.
Select maximum spacing or fixed target spacing, then set values.
Set an edge offset to keep bollards away from segment ends.
Use a safety factor above 1 for conservative spacing.
Click Calculate to view bollard count, spacing, and positions.
Use Download CSV or Download PDF for records and layout checks.

Spacing and Impact Control

Bollards perform best when spacing aligns with the impact and intrusion risk. Smaller spacing reduces the chance a vehicle can pass between posts, yet it can restrict pedestrian flow and equipment access. This calculator applies a safety factor by reducing the allowable spacing, giving tolerance for layout drift, base dimensions, and minor survey error.

Accounting for Openings and Clearances

Perimeters often include gates, loading doors, ramps, and utility zones where posts cannot be placed. Left and right clearances protect edge conditions and keep end posts away from walls, columns, or swing paths. Opening lengths reduce the protected run; when openings are frequent, segmenting the layout can represent separate continuous lines more accurately. Coordinate opening locations with operations teams to avoid blocking deliveries and emergency access.

Choosing a Spacing Strategy

A maximum spacing method computes the minimum bollard count that keeps final spacing at or below the limit. A fixed target method aims for a preferred spacing and adjusts the count to fit the available length. Maximum spacing is typically used for strict protection criteria, while fixed spacing supports consistent appearance and easier field measurement. Always compare the achieved maximum spacing to the requirement before issuing drawings.

Placement Offsets and Constructability

Edge offsets shift bollards inward from segment ends to reserve space for concrete cover, forms, and drainage features. Offsets also reduce clashes at corners and near foundations. The reported “actual spacing” reflects the usable length after offsets, helping reviewers validate anchor patterns and installation tolerances before procurement. If diameter is close to spacing, revise the layout to maintain workable drilling and grout clearances.

Documenting Layouts for Field Work

Position outputs measured from the run start simplify setting out. Crews can mark station points along a chalk line, confirm clearances, and reduce cumulative error. Segment summaries support quantity takeoffs and checking that each segment meets the spacing rule. CSV export integrates with drawings and spreadsheets, while the PDF report provides a durable record for inspections and closeout.

FAQs

1) What does the safety factor change?

It reduces the allowable spacing by dividing your spacing input. This adds conservatism for layout tolerance, minor measurement error, and practical installation variability.

2) Should I enter openings or segments?

Use openings for simple gaps that only reduce total protected length. Use segments when the run is truly broken into separate lines, such as multiple fence sections separated by gates.

3) Why use an edge offset?

Edge offset keeps bollards away from ends, allowing space for forms, concrete cover, drainage, and corner details. It can also reduce conflicts with nearby foundations.

4) What is “achieved max spacing”?

It is the largest spacing gap between adjacent bollards in the computed layout. Compare it to your allowable limit to confirm compliance.

5) Why does the count change when ends are excluded?

Interior-only placement centers bollards within the segment, which can reduce edge congestion. The calculator then distributes the usable length into equal cells, which can change the required count.

6) Can I use the position list for staking?

Yes. Measure from the run start, apply the listed station points, and verify clearances. For segmented layouts, stake each segment independently to maintain alignment.