A structured search for the cause of an air complaint, working from the people and the building to a cause before testingIn: IAQ investigation and testing field guide
IAQ monitoring vs investigation
Monitoring is continuous, real-time measurement that flags when air is bad; an investigation is a one-time hunt that diagnoses the cause of a complaintIn: IAQ monitoring and sensors field guide
IBN
Isolated bonding network, insulated but still bonded to the building ground at one controlled point, not a separate earthIn: Data center grounding and SRG
IBT
Intersystem bonding termination, the shared bonding point for telecom, CATV, and satellite per 250.94In: Grounding and bonding field guide
Ice freezing around a piling and lifting it as the water rises, ratcheting the piling out of the ground over wintersIn: Boat dock and marina construction
ICF
Insulating concrete form, a stay-in-place foam form that becomes the wall's permanent insulation and finish substrateIn: Formwork types and systems
ICMV
Intelligent compaction measurement value, a relative stiffness response from the drum accelerometer that varies by system and is not a density numberIn: Intelligent compaction for asphalt
ICP
Industrial control panel: the enclosure plus the power circuit plus the control circuitIn: UL 508A control panel and SCCR
ICRA
Infection control risk assessment, the required process for containing construction dust and protecting patients during workIn: Healthcare HVAC ventilation field guide
The unique, hierarchical string naming an element from building down to port, the same string carried on the label and in the recordsIn: TIA-606 labeling and administration
The IEEE guide that calculates incident energy and the arc-flash boundary; the calculation method, not the safety rulesIn: Arc flash study and labels
IEEE 48 class
The termination class, 1 through 3, set by whether it controls stress, insulates externally, and seals against the environmentIn: MV cable termination and testing
IEP
Indoor environmental professional, the independent industrial hygienist or consultant who assesses and clears without a stake in the remediationIn: Mold remediation field guide
Isolated ground, and isolated ground receptacle, the orange triangle-marked deviceIn: Isolated ground receptacles
IG-541 / FK-5-1-12
IG-541 is an inert nitrogen, argon, and carbon dioxide blend; FK-5-1-12 is a low-GWP fluoroketone halocarbonIn: Clean agent room integrity
IGU (insulated glass unit)
Two or more panes with a perimeter spacer and a sealed, usually argon-filled cavity; fails by edge-seal failure and fogging.In: Curtain wall and glazing
IGU / seal failure / fogging
Insulated glass unit, two or more lites sealed around a spacer; when the edge seal fails the cavity fogs and the unit is replaced wholeIn: Glass replacement and glazing repair
IGU seal warranty
The glass maker's warranty on an insulated unit's edge seal, which aftermarket film can void; confirm before applyingIn: Commercial window film
IGV
Inlet guide vanes, a ring of adjustable vanes at the impeller eye that modulate capacity by pre-swirling the entering refrigerantIn: Centrifugal chiller surge control
IICRC S500
The ANSI standard of care for water damage restoration, covering categories, classes, and dryingIn: Water mitigation and drying guide
Constant submersion in the stored product, the harshest coating exposure, demanding a product-matched liningIn: Tank coating and lining
Immobilizer / telematics
A device that blocks the engine from starting without a code or fob, and the GPS system that tracks location and alerts on movementIn: Jobsite security and theft prevention
Impact / tilt indicator
A shock or lean sensor on the crate that turns red when a threshold is exceeded in transitIn: Switchgear receiving inspection
Impact vs vibratory hammer
A hammer that drives with discrete blows and a blow count, versus one that shakes the pile in with no blow countIn: Driven pile foundations
A review obtained by offering something in exchange; offering compensation conditioned on a particular sentiment is prohibited under the FTC ruleIn: Customer communication and reviews
The one named person who runs the response, owns the decisions and tempo, and coordinates rather than performing the hands-on repairIn: Incident management and outage response
New corrosion forming in the parent concrete around a patch as the clean repair turns the surroundings anodicIn: Concrete spall repair
Incipient anode
New corrosion starting in old concrete just outside a patch repair, the ring or halo effectIn: Rebar corrosion protection
Incipient anode / halo effect
New corrosion in the old concrete ringing a fresh patch as the clean repair turns the surrounding contaminated steel anodicIn: Parking structure restoration
A drain that empties into an open receptor through an air gap or air break, not connected directly to the drainage systemIn: Indirect waste and air gap guide
A food-equipment drain that ends short of a floor sink, leaving an open vertical gap so a sewer backup cannot reach food equipmentIn: Kitchen equipment install field guide
Reading surface heat with a thermal camera to find hot connections, bearing heat, and failed steam trapsIn: Predictive maintenance guide
Infrared thermometer
Reads surface temperature at a distance; fast for scanning, but affected by emissivity and reads the surface, not the refrigerant insideIn: HVAC test instruments field guide
Rough-vacuum unit; atmospheric is about 29.92 inHg, and house vacuum reads in this rangeIn: Lab and process vacuum systems
Inhibited glycol
HVAC glycol carrying a corrosion-inhibitor and acid-buffer package; the only kind that belongs in a hydronic loopIn: Hydronic water and glycol field guide
The first 24 to 48 hours on site, held in a controlled temperature range under ASTM C31 with moisture loss preventedIn: Strength cylinders and acceptance
Initial vs aged
Initial is the fresh value; aged is measured after three years of exposure and is what codes requireIn: Cool roof reflectivity and energy
The insurance line that typically covers tools and mobile equipment on a jobsite, with a per-claim deductible the owner pays firstIn: Jobsite security and theft prevention
Inlet / intake air
The air entering the front of the IT equipment in the cold aisle, where the envelope is measuredIn: Thermal envelope and setpoints
The commissioning test where the plant rides a simulated failure at load without dropping the critical bus; its signoff is the centerpiece of a data center turnover packetIn: Proof packet assembly
Integrity test
An ELD survey run to verify a new or repaired membrane is breach-free before it is covered or acceptedIn: Electronic leak detection
Integrity testing / CSL
Post-pour tests for buried defects, including crosshole sonic logging (CSL), thermal integrity profiling, and sonic or pulse echoIn: Drilled piers and caissons
Rolling with a vibratory roller equipped with GPS, a drum accelerometer, a temperature sensor, a real-time display, and data logging that maps the workIn: Intelligent compaction for asphalt
Intensive
Deep media (6 in and up), shrubs to small trees, high load (often 50 to 150+ psf), garden-level maintenanceIn: Green roof installation
A direct patch from active equipment to a distribution panel; cheaper than a cross-connect but every change touches live gearIn: Cross-connect patch records
The time from queue entry through study and upgrades to actual energization, commonly years for a large loadIn: Data center site selection
Interior / selective demolition
Removing a building's finishes and non-structural elements down to the structure for a renovation or fit-out, while protecting what stays. Also called strip-out or soft strip.In: Interior demolition strip-out
Interior stain / drip
Where the water shows inside, after traveling along the deck and structureIn: Roof leak diagnosis
Interlayment
The 18 in No. 30 felt strip laid over each course of shakes as a baffle against wind-driven water; shakes only, not shinglesIn: Wood shake and shingle roofing
Interlock / isolation
An automatic action on a leak alarm that closes a valve, shuts a CDU, or stops a pump to cut the sourceIn: Leak detection commissioning
Interlock kit
A listed sliding plate on the panel that mechanically prevents the main and generator breakers from being on at the same timeIn: Generator interlock and backfeed safety
The diagram and rules that route construction equipment and workers on foot through the work area so the two stay separated, with marked routes, foot paths, access points, and no-go zones.In: Proximity warning and struck-by safety tech
A protection method that limits circuit energy so low that no spark or hot surface can ignite the atmosphere, even with a faultIn: Hazardous classified locations
Intrusion alarm system
Layered sensors that detect an unauthorized entry, report it at a keypad and a central station, and signal a response; a security system, not life-safetyIn: Intrusion alarm field guide
Two-digit ingress code: first digit solids and dust, second digit waterIn: NEMA enclosure ratings
IP vs analog camera
IP cameras are networked, megapixel, PoE-powered, and the new-build standard; analog and HD-over-coax run over coax and fit coax retrofitsIn: CCTV system design field guide
The voltage error in a current-on reading from soil resistance; removed by the instant-off measurement to get the polarized potentialIn: Cathodic protection field guide
IR window
A permanently installed infrared-transparent port that lets you scan an energized enclosure without opening itIn: Infrared thermography field guide
The loop vent, a hard-piped vent that rises under the counter and loops back below the floor to vent an island sink without an AAVIn: AAV and island vent guide
Islanding
Running disconnected from the utility, the on-site plant holding voltage and frequency on its ownIn: Data center on-site generation