Design Calculators

Chapter 9 — Five interactive real-time calculators for explosion-proof surveillance system design

The following five calculators cover the most critical quantitative design decisions in an explosion-proof video surveillance system. All calculations update in real time as you adjust the input parameters. Results are provided as engineering estimates; always verify critical values with detailed design calculations and consult the relevant standards before finalizing specifications.

Calculator 1: Camera Coverage & Lens Selection

Calculate the horizontal field of view (HFOV), vertical field of view (VFOV), and coverage area for a given camera sensor size, focal length, and mounting height. Use this to verify that a selected lens provides adequate coverage for the target area.

Sensor Size Focal Length (mm)

4.0 mm

Target Distance (m)

15 m

Mounting Height (m)

5.0 m

Camera Resolution (MP)

Horizontal Field of View

—

degrees

Vertical FOV—

Coverage Width at Target—

Coverage Height at Target—

Coverage Area—

Pixels Per Meter (PPM)—

Identification Suitability—

PPM Quality—

—

PPM Guidelines: Detection ≥25 PPM | Observation ≥62 PPM | Recognition ≥125 PPM | Identification ≥250 PPM (based on EN 62676-4)

Calculator 2: Storage Capacity & Retention Planning

Calculate the total storage required for a given number of cameras, resolution, frame rate, compression, and retention period. Results include raw storage, RAID overhead, and recommended NAS capacity with headroom.

Number of Cameras

Resolution Frame Rate (fps) Retention Period (days)

30 days

RAID Configuration

Recommended NAS Capacity

—

TB (usable)

Raw Data Rate—

Daily Storage—

Raw Retention Storage—

RAID Overhead—

With 20% Headroom—

Video data

RAID overhead

20% headroom

Storage estimates assume 24/7 continuous recording. For motion-triggered recording, apply a 0.3–0.5 reduction factor based on site activity level.

Calculator 3: Network Bandwidth Planning

Calculate the total network bandwidth required for video streams, management traffic, and storage replication. Verify that the network infrastructure can support the total load with adequate headroom.

Fixed Cameras (count)

Fixed Camera Bitrate (Mbps each) PTZ Cameras (count)

PTZ Camera Bitrate (Mbps each) Thermal Cameras (count)

Network Link Capacity (Gbps)

Total Required Bandwidth

—

Mbps

Fixed Camera Streams—

PTZ Camera Streams—

Thermal Camera Streams—

Management & Overhead (+10%)—

Link Utilization—

Bandwidth Composition

Fixed

PTZ

Thermal

Overhead

—

Recommended maximum link utilization: 70% for video networks. Above 70% risks packet loss and video quality degradation under burst traffic conditions.

Calculator 4: Fiber Optic Loss Budget

Calculate the total optical loss budget for a fiber link from camera to switch, including cable attenuation, connector losses, and splice losses. Verify that the total loss is within the SFP transceiver's power budget.

Fiber Type Cable Length (m)

500 m

Number of Connectors (pairs)

Number of Splices

SFP Transceiver Type

Total Optical Loss

—

Cable Attenuation—

Connector Loss (0.5 dB each)—

Splice Loss (0.1 dB each)—

SFP Power Budget—

Margin Remaining—

Loss vs. Budget—

—

A minimum 3 dB margin (safety margin) is recommended above the calculated total loss. If margin is less than 3 dB, upgrade to a higher-budget SFP or reduce the number of connectors/splices.

Calculator 5: UPS Runtime & Battery Sizing

Calculate the required UPS battery capacity to support the surveillance system for a specified runtime after power failure. Results include total load, required battery Ah, and recommended UPS kVA rating.

Number of Cameras (all types)

Average Camera Power (W each) Network Switches Total (W)

200 W

VMS Server + Storage (W)

800 W

Required Runtime (minutes)

60 min

UPS Battery Voltage (V)

Required UPS Rating

—

kVA

Camera Load—

Switch Load—

Server Load—

Total Load (W)—

Battery Capacity (Ah)—

Recommended UPS—

—

UPS efficiency is assumed at 90%. Battery capacity calculation includes a 1.25 safety factor. For cold climates (<0°C), increase battery capacity by 20–30% to compensate for reduced battery performance.