Questions we are asked before an order
Answered directly, including the ones where the honest answer is “it depends, tell us more”. Where a question concerns standards, we say what we can confirm and what we cannot.
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What is a confined space monitoring system?
A confined space monitoring system does three things at once: it measures the atmosphere inside the space, it tracks who is inside and for how long, and it manages the permit that authorises the entry. A gas detector alone does only the first. The distinction matters because most confined space fatalities involve a hazard that was detected but not communicated to the person who needed to act on it.
What gases are monitored inside a confined space?
Oxygen, carbon monoxide, hydrogen sulfide and combustible gas (LEL) cover the majority of industrial confined spaces and are the standard four-gas configuration. Specific spaces need additional or different sensors: sewer networks are dominated by hydrogen sulfide and methane, chemical vessels may retain solvent vapour or process-specific toxics, and inerted or purged vessels require oxygen measurement as the primary parameter. Tell us the space and its process history and we will confirm the sensor set.
Why do I need to sample at the workface rather than at the entrance?
Because a confined space atmosphere is not uniform. Vapour accumulates at the bottom of a vessel, hydrogen sulfide collects in low-lying sections of a sewer, and a detector held at the manhole reads a different atmosphere from the one a worker meets two metres further in. Pump-suction sampling with an extendable hose lets the sample be drawn from where the person will actually be working.
Does the equipment need a network connection to work?
No, and this is a deliberate design choice rather than a limitation. Inside the space, the internal unit communicates with the gas detector and wristbands over LoRa 2.4 GHz, so detection and local alarm continue in the signal dead zones typical of steel vessels and tunnels. The external unit handles the mobile uplink for remote notification. Where a plant cannot send data outside its own network, the platform can be deployed on-premise.
How does the system know how many people are inside?
Through the entry point. Personnel carry an RFID or Bluetooth wristband and register in and out at the entry monitoring device, which maintains the headcount and reconciles it against the permit. Over-occupancy and overtime alerts are raised automatically. In long tunnels, positioning along the run is combined with the entry log so that supervisors know not only how many are inside but where they are.
What happens if there is no mobile signal inside the space?
The alarm still reaches the entrant. The wristband and the internal unit both alarm locally on a threshold breach, and they communicate with each other over LoRa rather than through the mobile network. What is lost without a signal is the remote notification to the safety office, not the warning to the person in danger. For long runs, a cabled data bus carries detection, video and positioning along the tunnel.
Is a cable trench or a utility tunnel a confined space?
Yes — these are linear confined spaces: long, narrow, poorly ventilated, with few exits and a section that may be far from the access point. They defeat monitoring arrangements designed for compact vessels, because a unit at the entrance cannot see, hear or sample the far end. This is the case our cascaded linear monitoring system is built for, with coverage up to 1,000 m along a wired data bus.
Can confined space permits be handled electronically?
Yes, and doing so fixes a specific failure. Paper permits record that a signature was collected; they do not record that a briefing happened, what the atmosphere readings were at the time, or who was actually inside. An electronic workflow captures permit approval, pre-job briefing with audio and video, entrant authorisation, atmospheric records, alarm history and tool accountability as the work happens, with everything time-stamped and exportable.
What does a confined space monitoring system cost?
It depends on four variables rather than on a price list: the number of entry points, whether the spaces are compact or long tunnels, the sensor configuration (standard four-gas or custom), and whether you need public-cloud or on-premise deployment. Send us the space types, the number of points or units, and the standard you are audited against, and we will propose a configuration and a budget range rather than a list price that will not survive contact with your site.
What is the difference between a gas detector and a confined space monitoring system?
A gas detector measures the atmosphere at one location and signals locally. A monitoring system also manages the people and the process: who entered, under what permit, when, for how long, with what vital signs, and which tools went in and came out. Most incidents involve the second category of failure — a hazard that was measured but not acted on — which is why the equipment that detects is not the same as the equipment that controls.
What is low anchorage and why is it so dangerous?
Low anchorage is a fall-protection configuration where the lanyard is attached to a point at or below the worker's feet. It converts a short arrest into a long fall, increases the arrest forces on the body, and removes the clearance the system was designed around. It is dangerous because it is invisible from the ground: the harness is worn, the lanyard is connected, and the arrangement is wrong in a way only the wearer can see.
How does a smart safety harness detect that it is not being worn correctly?
A multi-axis posture sensor on the harness, combined with edge computing on the device, classifies the harness state — high anchorage, level, low, ground, suspended, free-fall, idle — and identifies specific violations such as a harness that is not worn at all, a hook that is not connected, or a lanyard anchored below the feet. Because the classification runs on the device, detection continues where there is no network coverage, which is exactly where steel erection and tower work take place.
Can a monitor be retrofitted to harnesses we already own?
Yes. The harness-mounted monitor is designed to fit existing full-body harnesses and can be installed by your own team, which is how most plants begin — a single crew and one harness type, before wider rollout. Where crews use several attachment devices, a multi-state monitor recognises pole straps, secondary lanyards, double hooks, fall arresters and self-locking devices on one control unit.
How do we keep an exclusion zone controlled without a permanent fence?
With an active boundary rather than a physical one. A battery-powered millimetre-wave radar unit scans a full 360° horizontally to 6 m, unaffected by darkness or weather, and a Bluetooth reader verifies whether the person entering is carrying an authorised tag. Anyone without a tag triggers a local alarm and a remote notification. Because it runs on battery with a magnetic base, the boundary can follow the work front rather than being installed once.
How do I know whether equipment is suitable for my hazardous area?
Match the equipment marking against your zone classification, and get the confirmation in writing. Our harness monitors and fence units are available in intrinsically safe versions rated Ex ib IIC T4 Gb. Send us your zone diagram and the equipment list you are considering, and we will confirm suitability rather than leave it as an assumption — an assumption here is difficult to reverse after installation.
What is the difference between ATEX, IECEx and Chinese explosion-proof certification?
They are different certification schemes addressing the same problem. ATEX is the European framework, IECEx is the international scheme, and Chinese certification is issued against national standards. Equipment certified under one scheme is not automatically accepted under another, although the underlying protection concepts (intrinsic safety, flameproof enclosure, and so on) are common. Tell us the scheme your site is audited under and we will confirm which certificates and test reports apply, and what additional documentation your authority may require.
Which fall protection standard applies to us — GB, ANSI or EN?
It depends on your jurisdiction and your insurer. GB 6095-2021 is the Chinese national standard and is what our supplied harnesses comply with as standard. ANSI Z359 applies in the United States and EN 361 in Europe. Where a project specifies ANSI or EN, raise it at enquiry stage so the applicable configuration and documentation can be confirmed before ordering rather than after delivery.
How long does deployment take?
Harness monitors retrofit to the existing harness in minutes and can be fitted by your own team; a fence unit is placed on its magnetic base with no wiring at all. Larger rollouts — issuing monitors across crews, or fencing several zones — are configured to order. Platform configuration, alert rules and user roles are set up with your safety team, usually remotely.
Can the system integrate with the safety platform we already run?
Interfaces for third-party platform integration are provided across the product range, and on-premise deployment is available where data cannot leave the plant network. Many operators use our monitoring equipment as the field layer beneath their existing platform, or run our platform and integrate the two where the existing system covers a different part of the process.
What documentation is supplied with the equipment?
Commercial invoice, packing list, certificate of origin, English manuals and labelling, third-party test reports for the relevant product line, and explosion-proof certificates for intrinsically safe models. Where your local authority requires additional documentation, tell us at enquiry stage and we will confirm what we can provide before you commit to the order.
No attendant can watch a confined space job continuously — what equipment automates monitoring and alarms?
Four device classes, each covering one failure of human attendance. A gas detection ball at the workface measures oxygen, carbon monoxide, hydrogen sulfide and combustible gas continuously and alarms locally on a threshold breach. A smart wristband on each entrant tracks heart rate and blood oxygen and carries an SOS call. An entry control unit at the access point registers who went in and keeps the headcount. A camera adds the visual record. On our LSM3000 monitoring station the external unit shows gas data, personnel status and video on one screen at the entrance, so the attendant sees what is changing inside without leaving the entry point.
Do we need a portable gas detector, a gas detection ball, or both?
Both, because they answer different questions. A pump-type portable detector draws samples point by point from the locations inside the space before entry — diffusion portables at the opening only read the air around the instrument. The detection ball is for during the job: it sits near the workface with a built-in pump, uploads readings automatically every 15 minutes instead of relying on hand-copied records that break at shift change, and carries a camera so the attendant can watch and correct the workface remotely. Judge entry with the portable; monitor the job with the ball, with both feeding the display at the entrance.
Can a harness be anchored to scaffold tubes or guardrails?
No. GB 23468-2025 rules out anchor points that are moving, low-strength, insecure or sharp-edged — guardrails, scaffold ledgers, pipework and cable trays included. Anchor to a concrete beam or column, a primary structural steel member, or a calculated anchor point; where none exists, rig a lifeline. The smart harness monitor checks that hooks were connected correctly — it cannot certify that the member takes the load.
How do workers stay tied off across a long rooftop run?
It comes down to two habits, not the device: connect first, then disconnect — confirm the new hook is secured before releasing the old one, with no gap in between. Plan the anchor spacing along the route before work starts; where anchors are scattered across a roof or steel structure, add a horizontal lifeline or rail so there is always a point to hook onto along the whole run.
How does a smart harness know a worker is above 2 metres?
It does not read a 2 m number — it reads air pressure. A high-precision barometric sensor measures relative height to roughly 0.6 m, with temperature compensation built in. A baseline is calibrated at the starting position before work; once the worker rises more than 2 m above it, monitoring switches to elevated-work mode. Calibration belongs in the pre-shift routine — a wrong baseline counts flat walking as climbing, or misses low-level work.
Is a smart harness monitor the same thing as a fall arrester?
No, and the difference decides what you are buying. A fall arrester takes over once a person is falling: it limits the drop distance and absorbs the arrest force, and it is the last line of protection — judged on how fast it locks and on whether it has been tested to GB 6095-2021. A harness monitor works before the fall: it watches whether the hook is connected at all and whether the anchorage sits where it should. Our monitor recognises an unconnected hook, anchorage below the feet and a dragging lanyard, alarms on the spot with sound and light, and files the event — while taking no part in load bearing. So it is not a choice between the two: configure the equipment to GB 23468-2025 first, then add monitoring to govern how it is used. Leave out either half and the other delivers less than it should.
Which positions on a site need fall protection monitoring?
Four positions cover it, and a smart harness monitor takes on the three that concern how a person moves at height. Edges and openings — where falls start most often — are handled by area-isolation alarms that trigger when someone crosses the boundary. Suspended platforms and scaffolds are where equipment worn on the person matters, because the working surface moves and a ground camera cannot see inside the basket: our multi-state harness monitor (SBM3000 series) confirms that both hooks are connected and that the anchorage sits above the attachment point. Ladders and towers are the stretch with the most re-anchoring, where GB 23468-2025 clause 4.3.5.3 points to a fall arrester or self-retracting lifeline and the monitor confirms no re-anchoring step is skipped. Access points are a separate category: they record who went in and how many people are inside.
How do we turn harness violation records into a dashboard?
Do not lift the alarm log onto the board unchanged — a crew dashboard tracks three things and only three. Who: a violation ranking by person and by crew, which is possible only because the monitor (SBM3000 series) is bound to a named wearer and files each event with name, employee ID, time and location; without identity you can show a total but cannot hold anyone to it, and records must match a named person to be retrievable under GB 23468-2025 at inspection. Fixed or not: incident, correction and re-check set side by side, with repeat violations of the same type flagged — that pattern usually points at anchorage layout or training rather than at the individual. When: time distribution read week by week, which shows which shifts run hot and is more useful than a raw count. The management platform filters and exports by crew, so no separate report is needed; set up the crew structure and the named ledger at handover and every board has an owner.
How do we pair fall arresters, SRLs and descent devices?
By how the worker moves, not by preference. A guided-type fall arrester travels a fixed vertical line and locks on the instant a fall begins — the fit for ladders, towers and shafts, and it must be matched to the rail or lifeline before purchase. A self-retracting lifeline (SRL) pays line out and takes it back as the worker moves, which suits steel erection, long pipe-rack runs and other work that changes attachment point often, and it still needs an anchor overhead with clear space below. A descent device lowers the user at a controlled speed under their own weight; it is escape and rescue equipment and must not be used as a fall arrest device, which is the pairing most often confused on site. GB 23468-2025, the selection, use and maintenance standard for fall protection equipment, states that where ladder climbing or frequent height changes are involved, a fall arrester or an SRL should be given priority. Our multi-state harness monitor (SBM3000 series) then covers the process side: an unconnected hook, an anchorage below the feet or a lanyard dragging on the ground is alarmed on the spot and filed, so attachment status can be checked after the fact. The monitor takes no part in load bearing.
Where should electronic fence units be placed on site?
Placement follows the type of risk point, and each type gets its own setting. Openings and edges: the gap is fixed and the area is small, so one unit facing the opening is enough, set to a low detection range so that people passing along the walkway do not trip it. High-voltage switchgear and live compartments: narrow but severe, so set a high range and whitelist the concurrent ID cards. Lifting zones: the work point moves with the load, so the unit follows the lifting point and the range leaves margin for the swing radius. Passage entries: these are routes people must use, so do not aim two units at the same entry or the alarms will repeat. That is the working scope of our smart electronic fence (EF1000-4G): it recognises an approach and raises a local alarm. Several local configuration standards list an electronic fence interlocked with video surveillance as a conditional item under the key supervision catalogue, tested by whether entry into the warning zone without completed work approval triggers an alarm — which is where the device's job ends. It does not replace work approval or supervision.
What should we check before a confined space kit is installed?
Three checks, and all three are awkward to reverse once the units are fixed in place. First, the packing list, item by item: control unit, gas detection ball or probes, wristbands, cables, brackets and chargers, with the spares reconciled against the contract. Second, the documentation — confirm that the intrinsically safe explosion-proof certificate and the third-party test report number are present and readable, and that the explosion-proof marking on the equipment nameplate matches the report, because a mismatch stops acceptance. Third, the point layout, which is the part that tends to get skipped: GB 46768-2025 requires at least three detection points in the vertical direction, with the upper and lower points no more than 1 m from the top and bottom of the space and the intermediate points no more than 8 m apart, an upper and a lower point being enough where the vertical height is under 2 m, and at least two points horizontally, the near point no less than 0.5 m from the entry and the far point no less than 2 m from it. Our LSM3000 series separates the internal unit, which travels with the workface, from the external unit at the access point, so walking the site drawing against the intended positions and communication distances on arrival is the step that prevents rework.
Permanent vs temporary electronic fence points: what changes?
Three settings change, and they decide whether a fixed installation still works once the novelty wears off. Whether the point moves: a job point goes out before the work and comes in afterwards, so the configuration is rebuilt every time, while a fixed point is installed once and watches continuously — which means the settings have to be right on day one rather than adjustable per job. Who is on the authorisation list: a job point issues cards against the work permit and clears them shift by shift, whereas a fixed point is authorised by post and changes only when staff transfer or leave, so the list is reviewed on the personnel event, not on the job. How power is planned: a job point takes one full charge per work cycle, while a fixed point needs rotation so units come out of service for charging in turn. Our smart electronic fence (EF1000-4G) is a self-contained unit for exactly that pattern: no wiring, IP65, a 12 V 5000 mAh battery charging in about 4 hours with roughly 15 days of runtime, a 360-degree microwave radar covering 0 to 6 m in two adjustable ranges, and short-range identification that lets authorised staff pass without an alarm while anyone else triggers sound and light locally. Two habits keep it alive: appoint units by the positions that need protecting rather than by job count — substation and high-voltage cabinet entries, hazardous chemical store doors, crane travel paths, restricted-area entries, one unit per point and several units tiling a large area with no connection between them — and route alarms to both the local sound and light and the phone under a duty rota that names who answers, because a fixed point normally has no attendant standing by. Keep the units energised when no permit is in force as well; a fixed point earns its place by keeping people out when no job is running. As with job-point use of the same equipment, it supports the permit and supervision process and does not replace either.
When a smart harness alarm fires, what do we check first?
A smart harness alarm should be triaged before it is answered, because our multi-state harness monitor (SBM3000 series) files alerts into three lines and the response order runs in different directions. Person-related alerts — silence, suspension, fall and fatigue — are confirmed before anything else: silence means no posture change was detected for a long period while working at height, which the product documentation flags as a possible loss of consciousness. Where a call gets no answer, the platform resolves the alarm to a named wearer and a position — dual-mode BeiDou and GPS for horizontal position, barometric sensing for height — and correction or accountability is discussed after the person is confirmed rather than before. Action-related alerts — hook not connected, anchorage below the feet, harness not worn, lanyard dragging on the ground — run the other way round: correct the wearer on the spot and the alarm stops, with the event logged against a real-name wearer and crew. Device-related alerts should not be allowed to lapse: on a low-battery warning, finish the move and reach a safe position before swapping or charging the unit, because shutdown stops posture assessment and alarming at the same time. Put battery level, alarm test and a clear sound outlet into the pre-shift check, at the interval GB 23468-2025 sets for maintenance and at least once a year where the standard is silent. The monitor identifies and alarms; it takes no part in load bearing and never locks off automatically, so the chain of anchor point, connector, lanyard and energy absorber still has to be selected and inspected to GB 23468-2025, and the body unit applies to users up to 100 kg under GB 6095-2021.
When a confined space monitor alarms, what is the response order?
Four steps, and they run in one direction: evacuate, retest, diagnose, record. Evacuation is not a judgement call — when the sound-and-light alarm goes, entrants leave by the agreed route and the attendant reconciles the headcount against the entry log, whether or not the reading falls back. Nobody goes back in until the space has been retested from outside: restore ventilation, then draw a pump-suction sample at the entry for oxygen, combustible gas, hydrogen sulfide and carbon monoxide, taking readings from the top downwards along the direction of entry, because GB 46768-2025 keeps the sequence of ventilate, test, then enter for a re-entry as well. Diagnosis separates a genuine exceedance (residual sludge still generating gas, or ventilation that stopped) from a disturbance caused by the work (hot work, desilting) and from a false alarm (a sensor blocked by dust, or calibration out of date); the first two go back through the permit-to-work process, the third takes the unit out of service for repair. Finally the alarm is filed against the job it interrupted — time, readings, actions taken and retest result against the permit. Our LSM3000 series stores alarm events and the detection curves as one timeline, so the export is the response record, and the headcount on the external unit at the access point reconciles with the evacuation count taken at the door. The equipment calls the exception out; the evacuation route and the retest procedure still come from the site's permit system.
How does a smart harness monitor help with manhole entry?
It covers one question across the whole descent — whether the person is properly attached — and it splits into three stages. Before entry, check the battery, binding and test alarm, and anchor to a structural member above the opening, since GB 23468-2025 clause 5.3.8.3 rules out guardrails and temporary pipework. During vertical travel, clause 4.3.5.3 calls for a rope grab or self-retracting lifeline, and the monitor watches for an unattached rope, an unattached grab or lifeline hook, low anchorage and a hook resting on structure without a positive connection, alarming at about 75 dB and pushing to the attendant's phone. At the bottom, a no-motion alarm matters more than a fall alarm: call out first, and follow the suspension rescue procedure rather than climbing in. The device carries no load; the tripod and lifeline do the holding.
Which type of intrusion prevention does a site actually need?
Four types, separated by what they do rather than by brand. Physical barriers — guardrails, covers, locks — stop people but do not alarm, so nobody knows when someone is over the rail. Warning and signage, such as barricade tape and notice boards, remind without blocking and only work alongside another measure. Area detection — radar fences and infrared beams — raises a local alarm the moment someone enters a zone, which is the case for temporary maintenance points that move with the work front. Identification and positioning — access control, ID cards, personnel locating — answers a different question: who came in, and were they authorised. The selection rule follows whether the hazard point is fixed: fixed points get physical isolation plus signage first; temporary or moving points where fencing is impractical get area detection; where you also need to know who entered, add card identification. Our EF1000-4G combines area detection and card identification in one unit, with radar coverage of 0–6 m in two ranges, no alarm for an authorised card, and a local sound-and-light alarm plus uplink for anyone unauthorised. It detects and warns; it does not block, and it does not replace the permit to work or the on-site attendant.
After retrofitting a harness monitor, what has to be checked?
Four checks, because a fitted monitor that is not verified is just a box that beeps. Mounting: the unit sits on the shoulder strap or waist belt with the factory clip and strap, with no webbing cut, no stitching opened and no connector altered, because it identifies and alarms rather than carrying load — in a fall the forces still run through the anchor, connector, lanyard, energy absorber and harness body. Clearances: nothing presses on the absorber pack and its deployment space stays clear; lanyard length under GB 23468-2025 is re-measured at 2 m or less after fitting, since a cable routed the long way round eats into working length; on double-hook work the monitor must not occupy either hook connection point. Alarm and height: trigger a test alarm and listen from 1 m away, because a speaker port under clothing or a strap muffles the roughly 75 dB output, and keep the pressure intake clear of waterproof fabric; the 2 m climb threshold is calibrated on site, so take the unit up and down once at the shaft mouth or on the platform. Validity and records: the harness stays in service if it is within its inspection period, checked at least annually, and the user's weight is within the 100 kg range of GB 6095-2021; the register then carries both the harness serial with its inspection date and the monitor serial with the person it is bound to.
Can an electronic fence stay outdoors in rain and heavy dust?
Yes, provided the rating and the mounting position are both right. The unit is IP65 as a whole: dust-tight, and protected against water jets from any direction, so it works through rain without a shelter. The condition is where it stands — no standing water. A unit in a low spot that floods will fail whatever its rating. Three routine tasks keep detection stable: wipe the radome with a damp cloth, because a thick dust layer in a workshop or on site degrades detection and scraping with a hard object damages the surface; keep the charging port and contacts dry, since charging a wet unit is how water gets inside; and inspect the housing and bracket after any impact from materials or tools, because a bent bracket shifts the detection zone with it. In cold weather runtime per charge shortens, so permanent points should rotate through charging by shift rather than being run flat.
Workers wear the harness but skip the hook: how to manage?
The violation is invisible at a distance: the webbing is on and the hook simply rests on a railing, which reads exactly like a proper connection from thirty metres away. The SBM3000 series monitor hands the judgement to the device — unattached, resting without a positive connection, hanging free and low-anchored use are identified locally at 1 to 5 second intervals, with a 75 dB alarm at the wearer and a push to the attendant's phone and the remote dashboard, each alarm written to a log. A barometric calibrator starts monitoring automatically above 2 metres, and dual 4G plus Bluetooth 5.4 keeps the local alarm alive where there is no signal. The unit retrofits onto existing harnesses. Management then needs three habits: a one-minute test alarm before each shift, alarm logs tied to crew reviews, and a named attendant watching the phone app — unanswered alarms turn the device into decoration within weeks.
Whose signature makes a confined space work permit valid?
Ask who signed before anything else: entry takes effect with the signature of a person explicitly authorised by the company, and a crew leader cannot approve his own entry — GB 46768-2025 requires an approval system, with no entry before approval. Three kinds of signatures appear on the permit, each covering one stage. The approver signs that the job may proceed, after checking the plan, gas readings, protective measures and training; the job supervisor and the attendant sign that their stage is in place, which confirms their part but cannot replace the approval. A missing signature means the paperwork is incomplete and the job does not start. The LSM3000 series integrated kit makes the permit checkable: a 10.1-inch outdoor unit at the entry, a standard 8 m cable extendable to 100 m to the gas probe in the shaft, concentrations logged at intervals no longer than 15 minutes, wristband entry and exit times in the access log, and over-limit alarms pushed to phones with a permanent record.
Do we need a portable gas detector or a monitoring system?
Neither replaces the other — they divide the work. A portable four-gas detector is the tool a person carries: it samples before entry and rides along during the job, but the data stays with the worker, and monitoring stops the moment the worker climbs out. A monitoring system keeps watching when nobody can: the gas detection ball sits at the workface, the control unit stands at the entrance, and the whole job — from entry to sign-off — is measured, logged and alarmed automatically. The standard is what turns this from a preference into a compliance matter: GB 46768-2025 requires continuous monitoring for the duration of the work, with gas concentrations recorded at intervals no longer than 15 minutes and the records retrievable after any incident. A portable detector reads the moment before entry; it cannot show whether the hydrogen sulfide at the bottom of the vessel rose during the job, by how much, or at what time — and when something goes wrong, the investigation will ask for the full record, not the opening reading. Whether a point needs the system comes down to three questions: is work there repeated, can anyone watch the job full-time while it runs, and can the readings be pulled up afterwards? One "no" means that point should be equipped as a system. The portable stays in the plan either way — for patrols and sampling. Our LSM3000 series follows the same split: internal and external units separated, concentrations logged automatically at 15-minute intervals, wristbands recording entry and exit, and over-limit alarms pushed to the attendant's phone with a permanent record — sort out the category first, then compare parameters.
Which harness do I need: work restraint or fall arrest?
Classify the job first, then decide about monitoring — that is the order a delivery check follows. GB 23468-2025 sorts harnesses into three classes by use: work restraint (Q) to keep a worker out of the fall zone, work positioning (W) for pole and tower work where the worker braces against the structure, and fall arrest (Z) for exposed work at edges or height. Where a job carries fall risk, the standard requires a full-body harness — a half-body belt or a single waist strap is not a substitute — and a worker who does both kinds of work is equipped for the higher-risk class rather than stretching one harness across both. Monitoring does not change this selection: the SBM3000 smart harness monitor retrofits to harnesses already in service and checks the attachment state of five tool types — positioning belts, second lifelines, double hooks, SRLs and rope grabs — so the standard governs the equipment selection while the device watches daily practice. Note the load limit: GB 6095-2021 applies up to a combined body-plus-tool load of 100 kg, and users above that need a separate assessment — there is no "heavy-duty version makes it compliant".
Does utility tunnel inspection need a confined space permit?
Entry is the dividing line. Reading gauges or log sheets at the entrance, or checking a manhole from outside, is routine inspection; opening a cover and going inside turns it into confined space work under GB 46768-2025 — approval, ventilation, gas testing and an attendant all apply, and a permit is issued as usual. A tunnel makes the paperwork hard to keep honest: inspection points are many, the route is long, and one round may open several access points, so a paper permit travelling with the crew keeps slipping out of sync with what is happening on site. The LSM3000 linear monitoring series moves approval and access online: staff swipe in and out at each portal, and the permit, the people and the workface reconcile automatically. For tunnels with frequent rounds, manage permanent access points and temporary work points separately — simplified logging for routine rounds, the full permit process whenever anyone enters to work.
How many monitoring nodes does a linear confined space need?
Spacing follows function, not length. Where the goal is personnel tracking and data coverage, node receivers are mounted at even intervals along the tunnel wall, and denser spacing gives finer location; where the goal is entry control alone, the two portals are what matter. A straight run of a few hundred metres with no junctions and no intermediate workfaces works with entry monitoring at both ends plus evenly spaced nodes, while every junction or connecting shaft needs an added node — without one, a worker who turns into the branch drops out of view. Nodes are chained on a single data bus that reaches a kilometre, so no node needs its own power drop or network cable. The layout does not have to be calculated by hand: before delivery the tunnel drawings are walked through — portals, junctions, workfaces — and node count and positions are stated in the proposal, with per-section occupancy visible on the entry screen after commissioning.
How do we manage monitoring across dozens of sumps and wells?
Give each point a number from the plant's identification register and bind one unit to one point, with that number printed on the device label. When the register line carries the point, the unit, the permit history and the alarm log, an inspection is answered from one line instead of a paper folder, and a contractor crew arriving at the opening can read the label and know which sump the unit covers. Cable runs follow distance rather than convenience: with the indoor and outdoor units separated, the outdoor unit stays at the access point and the standard 8 m probe cable extends to 100 m, so dispersed sumps do not have to be clustered to save cable, and each unit feeds its own entry screen so a patrol reads it while walking past. What decides whether dozens of points stay under control is ownership of the alarm: name the person who answers each point, write it into the permit procedure, and make "no leaving post until acknowledged" the rule. Sites that have run this for a while report the same failure mode — an alarm nobody owns, rather than an alarm that never sounds.
Do confined space monitoring setups differ by space type?
Yes — and treating them as one configuration is where monitoring gaps come from. Yunku sorts spaces into three types. Lines: utility corridors and tunnels, where the challenge is distance — gas detection cannot stop at the entrance, so the indoor unit advances with the work section and data reaches the attendant through the outdoor unit at the portal. Points: sewer manholes and similar small openings, where entry is by rope ladder or tripod and the equipment has to hold at the mouth — test the bottom and mid-section before entry, keep monitoring continuous, put a wristband on each entrant, and ask about ingress protection and corrosion resistance because corrosive gases are common. Vessels: reactors and tanks, where hot work and cleaning stratify gas into layers — detection points cover top, middle and bottom, ventilation and monitoring run throughout, and entry follows testing and ventilation to GB 46768-2025. The acceptance thresholds are shared across all three: oxygen 19.5%–23.5%, flammable gas below 10% of the lower explosive limit, toxic gases within GBZ 2.1-2019. Main units are interchangeable; front-end sensors and mounting change with the space — spell out space type, depth or diameter, and corrosive media before ordering.
Does confined space monitoring need a screen operator?
No. The value of the system is that it comes to you only when something is wrong — not that someone is watching. The LSM3000 series monitoring station ships with alert-push logic: gas over limit, an abnormal personnel state, or overtime without exit is sent automatically to the assigned manager's phone and the platform, so nobody on duty has to keep staring at a screen. The practical arrangement folds alert reception into the existing safety or gate duty roster: receivers are assigned by monitoring point, so whoever owns the area receives the push, and night coverage runs on automatic push plus phone escalation — no new position is created. Do one thing right after commissioning: configure the push rules — who receives, how severity is graded, and how long without acknowledgement before escalation — and write those three into the work plan. That does more than adding a head to watch the screen. The system fills the gap of what cannot be seen or continuously supervised; approvals, ventilation and the attendant cannot be skipped.
Does installing confined space monitoring stop production?
Usually not. The equipment takes the retrofit route: the outdoor unit stands at the entrance, the indoor unit and the gas detection ball go on the workface, power up and join the network — no process piping touched, no connection into production systems, and a single set typically goes from arrival to in-service within a few hours. The installation list is short: fix the outdoor unit beside the entrance with the screen facing the attendant, place the indoor unit and detection ball per the GB 46768-2025 point requirements — at least 3 points vertically and 2 horizontally — and run one network cable, 8 m standard and extendable to 100 m. Three site types need lead time with production planning: drilling and cabling in explosion-protected areas requires hot-work permits, linking into the corporate network or an existing platform needs IT cooperation, and kilometre-long corridors take longer to cable in cascade — schedule those in a maintenance window. Delivery day covers point-by-point verification, alarm values, permit linkage and attendant training within half a day, and old plants without spare power or a network port run on battery plus 4G, with the emergency battery carrying 6–8 hours after mains loss.