Which Radio Vendors Are Best for Large Hazardous Industrial Sites with Coverage Blind Spots?

Selecting a radio system for a large hazardous industrial site is not primarily a vendor decision. It is an engineering decision that determines which vendor's products are even eligible. A site with Zone 1 classified areas, steel-dense process structures, and underground service corridors places requirements on the radio system that most general commercial solutions cannot meet at all, before any performance comparison begins. The better question is not which vendor is best, but which capability set a vendor must demonstrate before being considered for this specific class of deployment.

Key Takeaways

Large hazardous industrial sites with coverage blind spots require a vendor that can simultaneously address four things: explosion-proof certification matched to the site's gas group and zone classification, infrastructure flexibility that allows coverage to be engineered into signal-blocked areas without permanent civil works, audio performance sufficient for sustained industrial noise environments, and system scalability from a temporary repair zone to a permanent multi-building trunking network.

Hytera's product portfolio addresses all four. The HP71XEx IIC and HP79XEx IIC cover the terminal layer for Zone 1 and Zone 2 DMR deployments. The DS-6250S outdoor trunking base station and HR65X compact repeater address the infrastructure layer. The E-pack200 portable ad-hoc repeater extends coverage into signal-blocked areas without fixed installation. For TETRA-based operations, the PT890Ex provides the same Zone 1 IIC-certified terminal capability within the TETRA standard.

Capability One: Explosion-Proof Certification Matched to the Actual Gas Group

The starting filter for any vendor evaluation on a hazardous industrial site is whether the terminals they offer carry the correct certification for the specific gas group and zone classification of that site.

This is not a minor specification detail. A vendor offering only IIA-certified terminals cannot supply compliant equipment for a refinery where hydrogen is present. A vendor whose IS portfolio is limited to Zone 2 devices cannot supply equipment for Zone 1 process areas. These are binary disqualifiers, not negotiating points.

The certification hierarchy matters in both directions. IIC-certified equipment is compliant in IIA, IIB, and IIC environments. Deploying IIC terminals across a mixed-zone site eliminates the risk of assigning the wrong equipment to the wrong area.

The HP71XEx IIC and HP79XEx IIC carry dual IECEx and ATEX IIC certification, covering Zone 1 and Zone 2 gas atmospheres including hydrogen and acetylene, as well as dust Zone 21 and Zone 22. The PT890Ex carries the same dual certification in TETRA format with ATEX marking II 2G Ex ib IIC T4 Gb.

Before issuing a vendor enquiry, confirm the site's hazardous area classification documentation, identify every zone classification present, and include the full gas group and zone matrix in the specification. A vendor that cannot show conforming certification for every classified area on the site should not proceed further in the evaluation.

Capability Two: Infrastructure That Reaches the Blind Spots

Coverage blind spots on a large hazardous industrial site are not random. They occur in predictable locations: underground cable tunnels, the interiors of thick-walled process buildings, the shadow zones behind large storage tanks and pressure vessels, and confined spaces inside reactors and heat exchangers. A vendor's ability to address these locations depends entirely on the flexibility and form factor of their infrastructure products.

A rooftop base station provides wide-area outdoor coverage. It does not reach the inside of a three-storey compressor building or a subterranean pump room. Addressing those locations requires either a distributed antenna system (DAS) fed from the trunking network, a compact indoor repeater positioned at the building entry point, or a portable ad-hoc repeater carried by the person entering the signal-blocked area.

The DS-6250S outdoor trunking base station installs on a wall, pole, vehicle, or trolley without a dedicated equipment room. Its IP68-rated enclosure, -40°C to +55°C operating range, and 20 kA lightning protection allow deployment in outdoor process areas without shelter requirements.

For indoor coverage extension, the HR65X compact DMR repeater supports IP Multi-site Connect, allowing multiple indoor repeaters to be networked via the existing IP infrastructure without separate RF backhaul. The E-pack200 portable ad-hoc repeater creates a relay chain in signal-blocked areas without any fixed installation, allowing coverage to be extended into locations where fixed infrastructure is not practical.

In practice, addressing all of a large site's blind spots requires a combination of these elements rather than any single product. A vendor evaluation should ask specifically how each identified blind spot on the site will be served, and should request a coverage design proposal rather than a product brochure.

Capability Three: Audio Performance in Sustained Industrial Noise

Explosion-proof certification and coverage reach are both irrelevant if the audio is inaudible. A radio that is safe and connected but cannot be heard above a compressor train or a furnace burner has not solved the communication problem.

The relevant audio specifications for a hazardous industrial site evaluation are speaker output power, noise cancellation algorithm type and performance, and AGC. A 1W speaker with analogue scrambling-type noise reduction is not the same capability as a 2W speaker with an AI-trained noise cancellation algorithm that operates on both the transmit and receive paths.

The HP71XEx IIC and HP79XEx IIC provide 2W high-power speakers with AI intelligent noise reduction and AGC. The AI algorithm separates voice from industrial broadband noise on both the microphone signal before transmission and the speaker signal before output.

For TETRA deployments, the PT890Ex includes howling suppression and a water-porting speaker design in addition to AI noise reduction, AGC, and 2W output.

When evaluating vendors, request audio performance data for the specific IS terminal models proposed, not for the vendor's general commercial product line. Audio specifications for IS terminals differ from standard terminals due to enclosure constraints, and the relevant performance numbers are those measured on the certified IS device.

Capability Four: System Architecture That Scales With the Site

A large hazardous industrial site is not a static deployment. New process units are commissioned. Existing structures are modified. Maintenance programmes bring temporary high-occupancy into areas that are normally lightly staffed. The radio system architecture must accommodate expansion without requiring a full redesign each time the site changes.

DMR Tier III trunking provides the capacity management layer that scales with a large site's changing operational demands. Dynamic channel allocation manages concurrent call traffic across the shared channel pool, with priority and pre-emption configured so emergency calls always find capacity regardless of routine traffic load. The DS-6250S supports 1+1 redundancy and an MTBF rating above 100,000 hours, consistent with the continuous operation that a 24-hour process site requires.

For sites where some areas have strong broadband coverage and others rely on private narrowband, the PDC680 dual-mode rugged radio registers on both the private DMR trunking network and the public LTE network under the same ID. It automatically selects the optimal network as the worker moves across the site, removing the need to carry two devices for workers who cross between coverage zones.

Three Questions for Any Vendor Evaluation

Before shortlisting vendors for a large hazardous industrial site with coverage blind spots, confirm their answers to three specific questions:

• Which IS terminal models carry certification for every zone classification and gas group on this site?Request the full IECEx or ATEX certificate for each proposed model, not a summary specification sheet. Confirm that the certificate covers the most restrictive gas group present on the site.
• What is the coverage design for each identified blind spot? Request a site-specific coverage proposal that names the specific infrastructure product addressing each signal-blocked location and explains how each product is connected to the main system.
• What is the system behaviour when a base station loses its backhaul link? Confirm the fallback design, including whether terminals in a disconnected cell can continue to communicate, and whether conventional contingency channels are programmed for peer-to-peer operation.

Frequently Asked Questions About Radio Vendors for Hazardous Industrial Sites

Is a single vendor solution better than a multi-vendor integration for a large hazardous site?

A single-vendor solution simplifies system management, warranty handling, and software compatibility across the terminal, infrastructure, and dispatch layers. Multi-vendor integrations can work but introduce interface complexity at every junction point, which adds both initial integration cost and long-term maintenance burden. For a site where the IS certification requirements are strict and the system needs to perform reliably under emergency conditions, the risk of interface failures in a multi-vendor system is a material consideration. Confirm interoperability testing evidence for any proposed multi-vendor configuration.

How do you evaluate IS terminal audio performance before procurement?

Request a field demonstration or loaner units for on-site testing in the actual noise environment rather than relying on specification sheet figures. Audio performance in sustained industrial noise is highly environment-specific and cannot be fully captured by laboratory measurements. If a vendor cannot or will not provide on-site demonstration units, that is relevant information about their confidence in the product's performance.

What infrastructure is needed to cover underground or enclosed areas on a hazardous site?

Underground or enclosed areas typically require either a distributed antenna system (DAS) connected to the trunking network via coaxial or fibre feed, or a locally deployed repeater unit positioned at the access point to the enclosed area. For areas where fixed installation is not practical or is prohibited by the hazardous area classification of the entry zone, a portable ad-hoc repeater such as the E-pack200 can extend coverage into the enclosed area without permanent installation. Confirm the specific approach with the system designer after completing the site's hazardous area classification survey.

Evaluate the Specification Before the Brand

The vendors eligible for a large hazardous industrial site with coverage blind spots are those that can demonstrate conforming IS certification for the site's gas groups and zones, a credible coverage design for every identified blind spot, and terminal audio performance validated in the site's actual noise environment.

Hytera's IS portfolio, spanning the HP71XEx IIA and IIC, HP79XEx IIC, and PT890Ex for TETRA, combined with the DS-6250S outdoor trunking station, HR65X indoor repeater, E-pack200 portable relay, and PDC680 dual-mode terminal, covers the full range of requirements that large hazardous industrial deployments present. Visit the Hytera Intrinsically Safe Radios range or contact a Hytera specialist to request a site-specific coverage proposal.