Engineering Tools
A free toolkit of 134 calculators for electrical, lighting, low-current and energy engineers, in seven categories. Search by name or by standard. All calculations run in your browser. Nothing is sent to a server.
A free toolkit of 134 calculators for electrical, lighting, low-current and energy engineers, in seven categories. Search by name or by standard. All calculations run in your browser. Nothing is sent to a server.
For preliminary estimation only. Before using calculator results for project decisions, obtain independent verification from a suitably qualified, licensed engineering consultant. Review the assumptions and references provided with each calculation. Engineering calculator terms
Calculate line current from real power, voltage, power factor, and motor efficiency. Supports 1-phase and 3-phase circuits.
Formula: I_line = P / (V · PF · η) for 1-phase · I_line = P / (√3 · V_LL · PF · η) for 3-phase. In Star: V_phase = V_LL/√3, I_phase = I_line. In Delta: V_phase = V_LL, I_phase = I_line/√3.
Pick the smallest cable that satisfies both ampacity and voltage drop. Two standards: IEC 60364-5-52 (Method C, mm² cross-section) or NEC Table 310.16 (single conductor in raceway, AWG sizes). Cu conductors.
Nominal Cu cross-sections. Ampacity: IEC 60364-5-52 Table B.52.4 (2 loaded conductors 1φ, 3 loaded 3φ) or NEC 310.16, with ambient and grouping factors. Drop: Vd = k·I·L·(R cos φ + X sin φ)/1000, k = √3 (3φ) or 2 (1φ), R at 70 °C (PVC) or 90 °C (XLPE), X at 60 Hz.
Standalone Vd calculation for a known cable size. Use to verify a sizing decision or check existing installation.
Vd = k·I·L·(R cos φ + X sin φ)/1000, k = 2 (1φ) or √3 (3φ). R from IEC 60228 at 70 °C or 90 °C; X = 0.096 Ω/km at 60 Hz (IEC 60364-5-52 Annex G).
Average illuminance using the lumen method: E = (N · Φ · CU · LLF) / A. Calculates lux at the floor and at table-top height (0.75 m).
Lux at floor uses RCR(h_room). Lux at table top uses RCR(h_room − 0.75 m). CU is interpolated from typical direct-luminaire tables.
Diameter of the light circle a spot or downlight throws on a surface, plus the illuminated area and center illuminance. Geometry: D = 2 · d · tan(θ / 2).
Spot diameter D = 2 · d · tan(θ/2). Illuminated area = π · (D/2)². Center illuminance E = I / d² (inverse-square law, beam axis perpendicular to the surface).
kVAR of capacitor bank required to lift the existing power factor up to the target. Q = P · (tan φ₁ − tan φ₂).
Saudi utility tariffs commonly penalise power factor below 0.85 (confirm the current SEC clause). Industrial practice targets 0.95, not unity. Grid: 60 Hz.
Build the connected load list, set runtime and battery voltage, get the recommended UPS rating in kVA + battery capacity in Ah. Defaults match a typical NLC field-equipment-cabinet (FEC) project. 230/400 V, 60 Hz.
Total W = Σ(qty × W) × cabinets + UPS self × cabinets · kVA = W × (1 + margin) / (PF × 1000) · Battery (IEEE 485): I = W / η_inv / V_end, Ah(C10) = I × h × 1.25 aging / K_t(h)
Size a solar PV system from daily energy use, estimate generation and savings, and (for off-grid) the battery bank. Defaults tuned for Saudi irradiance.
Array kWp = Daily kWh / (Sun hours × PR), with PR = 1 − losses. Generation = kWp × Sun hours × PR. Off-grid battery kWh = Daily kWh × autonomy / (DoD × efficiency).
Charging time, the circuit current and recommended breaker & cable for an EV charger, plus total demand for sizing the distribution board.
Time = energy to add / (charger kW × efficiency). I = P/V (1φ) or P/(√3·V) (3φ); DC chargers: I = P/(k·V·η_ac). Breaker ≥ 1.25 × I (continuous, SBC 401 / NEC 625.41). Cable per IEC 60364-5-52 with ambient and grouping factors. Total demand = N × kW × diversity.
Size a distribution transformer from connected load, power factor, demand and future-growth factors. Returns the next standard kVA, loading, and LV breaker.
kVA = Load × demand × (1+growth) / PF. FLC = kVA·1000 / (√3·V).
Compare existing fixtures to LED: annual energy, cost and CO₂ saved, plus simple payback.
kWh/yr = qty × W × hours × days / 1000. Saving = (old − new) energy × tariff.
Estimate recording storage, total bandwidth and the recommended HDD for an IP camera system.
GB = bitrate(Mbps) × 0.125 × 3600 × hours × days / 1000. H.265 ≈ 0.55 × H.264.
Number of emergency luminaires for an escape route and whether the battery meets the required duration.
Luminaires = ceil(length / spacing) + 1, plus one at each exit / direction change. Autonomy = battery Wh × converter efficiency × end-of-life capacity / power W × 60.
Installed lighting power per m² against a typical energy-code limit, with pass / fail and headroom.
LPD = (fixtures × W + other) / area. Allowed = code limit × area.
Pole spacing for a target average illuminance by the lumen method, with the spacing-to-height ratio.
Spacing S = k × (Φ × MF × UF) / (E_avg × width); k = 1 single-side, 2 staggered / opposite.
Total PoE load against the switch budget, per-port class, and power lost over the cable to each device.
Total = devices × allocation. Loss = I²·R_loop, I = P / V_PSE (44 V Type 1, 50 V Types 2 to 4), R_loop = 2·ρ(T)·L / pairs + 1 Ω connectors; 4 pairs for Types 3 and 4.
Standby generator size from connected load, power factor, demand, motor-start allowance and growth.
Formula: P = load × demand × (1+growth) × (1+surge); set kVA ≥ max[ P / (PFload · k), P / (PFrated · duty · k) ], k = 1 − derate.
Average canopy PPFD and daily light integral for horticulture projects: PPFD = N · PPF · UF / A, then DLI = PPFD × hours × 3600 ÷ 10⁶.
PPFD is the photosynthetic photon flux density over the PAR range (400 to 700 nm). Results are canopy averages; uniformity depends on mounting height and optics. Learn more on our Horticulture Lighting page.
What a datasheet luminaire actually delivers at the site ambient. Datasheets are measured at Ta 25 °C (LM-79); Saudi sites run at 45 to 55 °C.
Lumens(Ta) = lumens₂₅ × [1 − (1 − ratio₅₀) × (Ta − 25)/25]. Life: indicative halving per 12 K of junction rise. Evidence: LM-84 + TM-28 and ISTMT at 50 °C, LM-80 + TM-21 at the measured Ts.
Battery and PV module for a stand-alone solar street light from the nightly energy, autonomy and the worst-month sun hours.
E_night = W × dim × h. Battery Wh = E_night × autonomy / DoD. PV Wp = (E_night + usable battery Wh / recharge days) / (PSH × derate × η_controller × 0.95 charge).
MF = LLMF × LSF × LMF × RSMF per CIE 97 (interior) and CIE 154 (exterior), with a desert-dust pollution category.
LLMF = 1 − 0.3 × (hours to the evaluation point / L70), linear to L70. LMF from the CIE 154 table for the sealing, pollution and cleaning interval. Initial design value = target / MF.
Required illuminance, uniformity and glare limit for a sport and competition class, with a first luminaire count by the lumen method.
N = E × A / (Φ × MF × UF). Class values from EN 12193 Annex A (indicative; verify against the 2018 edition and the federation's own rules for TV).
Screen an LED road luminaire against the SASO 2927:2019 (Lighting Part III) requirements as SASO presents them, and list the registration evidence.
Checked against secondary-source values (SASO 2927:2019 as reproduced in a SASO workshop): L70 ≥ 50,000 h; CCT 3000 to 6000 K; PF ≥ 0.9; THD < 15 %; surge 10 kV installation / 4 kV internal; 120 to 277 V AC, 60 Hz. Not assessed (unresolved or not verified): efficacy and chip ratio, IP66 / IK08, controls and NEMA socket.
Turn a rated Lx figure into calendar years at the real operating profile, and check the TM-21 6× projection limit.
Years = hours / (h/day × days/year). Site life ≈ rated × 2^(−(Ts_site − Ts_rated)/12) (indicative Arrhenius rule). TM-21 allows a projection of at most 6 × the LM-80 test duration.
Daily light integral from a canopy PPFD and photoperiod, or the PPFD needed for a crop's DLI target.
DLI = PPFD × hours × 3600 / 10⁶. PPFD needed = DLI × 10⁶ / (hours × 3600). Crop ranges are typical horticultural targets; the grower's recipe governs.
Luminaire surge immunity and the board SPD that protects it, from the exposure, the earthing system and the circuit level.
Luminaire immunity per IEC 61547 / IEC 61000-4-5 (differential L-N, common L-PE). Board SPD per IEC 61643-11 / IEC 60364-5-534: Type 2 at distribution level, Type 1+2 where an LPS or overhead line exists. Uc ≥ 1.1 × Uo (275 V) in TN; add N-PE in TT.
Threshold, transition, interior and exit luminances by the CIE 88 L20 method, from the design speed, access luminance and traffic.
Lth = k × L20 over the first half of the stopping distance, then down to 0.4 × Lth. Transition L(t) = Lth × (1.9 + t)^−1.4 until it meets the interior level. Exit zone rises to 5 × interior over the last 50 m.
Energy and cost saved by occupancy, daylight, scheduling and tuning strategies on an installed lighting load, with simple payback.
Combined saving = 1 − Π(1 − sᵢ), capped at 55 %. Baseline kWh = kW × h × days. Typical fractions from the LBNL meta-analysis of field studies (occupancy 24 %, daylighting 28 %, tuning 36 %, multiple strategies 38 % on average).
Generate a ready-to-paste specification clause or BOQ line for any NLC luminaire. All values come from the official NLC datasheets.
Need datasheets, photometric (IES/LDT) files or BIM content? Ask us through the contact page.
Put two or three NLC luminaires side by side. All values come from the official NLC datasheets.
Need the numbers in a specification? The Spec Writer turns any of these products into a ready-to-paste clause.
Narrow down NLC families by application and specs. Filters are optional; leave a field blank to skip it.
Filters read the published specs on each product page. A family whose page does not state a spec is set aside rather than guessed at, and counted below the shortlist. Each product page carries its own datasheet.
Prospective three-phase fault current at the transformer terminals and at a downstream board, with the breaking capacity to specify. Basis: IEC 60909-0, SBC 401.
Formula: Ik'' = c · Un / (√3 · |ZQ + ZT + ZL|), c = 1.05 · ZT = (uk/100) · Un² / SrT · ZQ = c · Un² / S''kQ · ip = κ · √2 · Ik'', κ = 1.02 + 0.98 · e−3R/X
Cable cross-section against the raceway internal area, with the smallest size that passes. Basis: NEC Chapter 9 Table 1 (conduit), 45 % space factor for trunking (IET guidance to BS 7671).
| Cable group | Quantity | Outer diameter (mm) |
|---|---|---|
| 1 | ||
| 2 | ||
| 3 |
Formula: Acables = Σ ni · π · di² / 4 · fill % = Acables / Araceway · 100 · limits: n = 1: 53 %, n = 2: 31 %, n ≥ 3: 40 %, trunking 45 %
Resistance of driven rods or a buried conductor in uniform soil, rods in parallel, and the effect of a low-resistivity backfill. Basis: BS 7430, IEEE 80.
Formula: Rrod = ρ / (2πL) · [ln(8L/d) − 1] · Rstrip = ρ / (2πL) · ln(L² / (1.85 · h · d)) · Rencased = ρb / (2πL) · ln(D/d) + ρ / (2πL) · [ln(8L/D) − 1] · Rn = R1 · (1 + λα) / n, α = ρ / (2π R1 s)
Triplen harmonics from LED drivers and IT loads add up in the neutral of a 4-wire circuit. Neutral current, cable sizing basis and transformer K-factor. Basis: IEC 60364-5-52 Annex E, IEEE C57.110.
Harmonic spectrum, % of the fundamental (typical LED driver mix shown, editable)
Formula: THDi = √(Σ hn²) · I1 = IL / √(1 + THD²) · IN = I1 · √((3 · √(h3² + h9²))² + u²) · K = Σ hn² n² / Σ hn²
Rating after ambient derating, voltage drop for an end load or a distributed riser, and losses. Basis: IEC 61439-6.
Formula: IB = P / (√3 · V · cos φ) · In · kθ ≥ IB · ΔV = kd · √3 · IB · L · (R cos φ + X sin φ), kd ∈ {1, 0.5} · Ploss = 3 · IB² · R · L (one third for a distributed load)
Magnetizing inrush on energization against an IEC standard-inverse relay with an instantaneous element, and the 2 s short-circuit withstand point. Basis: IEC 60076-5, IEC 60255-151, IEC 60282-1 (editions not verified); fuse choice from manufacturer data.
Formula: In = S / (√3 · U1) · i(t) = k · In · e−t/τ · trelay = TMS · 0.14 / ((I/Is)0.02 − 1) · D = ∫ dt / trelay(i(t)) [i > Is], D ≥ 1 · Ithrough = In / uk @ 2 s
Cell count from the voltage window, a simplified duty-cycle capacity with design margin, ageing and temperature factors, and the charger rating. Basis: IEEE 485-2020 (lead-acid), IEEE 1115 (NiCd, edition not verified).
Formula: n = ⌊Vmax / Vfloat⌋ · Vend = Vmin / n · Ah = (Ic · T + Itrip · 1/60 + Iclose · 1/60) × kmargin × kageing × kT · Icharger = 1.1 · Ah / tr + Ic
Bus voltage dip when a large motor starts, by the impedance method, for each starting method, and the largest starting current the limit allows. Basis: IEEE 399 (Brown Book), IEEE 3002.7.
Formula: Ist = k · In · Zm = U² / (√3 U Ist) ∠ acos(0.3) · Zs = U² / Ssc ∠ atan(X/R) · ΔV = 1 − |Zm| / |Zs + Zm|
Peak inrush and frequency when a step is switched alone or back to back with energized steps, the inductance needed to stay within 100 × In, and the detuned tuning frequency. Basis: IEC 60831-1, IEC 60871-1, IEEE 18.
Formula: C = Q / (ω U²) · single Î = In √2 √(Ssc/Q), f = f1 √(Ssc/Q) · back to back Î = U √(2/3) √(Ceq/L), Ceq = C · n / (n + 1), f = 1 / (2π √(L Ceq)) · Lmin = Ceq (U √(2/3) / 100 In)² · h = 1/√p
Screening estimate of the risk of loss of human life R1 (components RA, RB, RU, RV) for one zone, and the lowest LPS class with coordinated SPDs that brings it below the entered tolerable risk. Basis: IEC 62305-2:2010 method (historical edition; the 2024 edition changes the method), IEC 62305-3.
Factor lists below (CD, LF, rf, rp, hz, rt, CI, CE) follow the 2010 annexes Assumed value: reference not verified
Formula: NG = 0.1 Td · AD = LW + 6H(L + W) + 9πH² · ND = NG AD CD 10−6 · NL = NG · 40 LL · CI CE 10−6 · R1 = ND(PALA + PBLB) + NL(PULU + PVLV)
Tension build-up section by section in a horizontal duct run, sidewall bearing pressure at each bend, both pull directions. Basis: IEEE 1185, IEEE 576 (pulling guidance), AEIC CG5.
| # | Section | Length (m) or angle (°) | Bend radius (m) |
|---|---|---|---|
| 1 | |||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
Formula: straight T2 = T1 + W · g · f · L · bend T2 = T1 · ef θ · SWBP = T2 / R · Tmax = σ · A · n
Compensation current to bring a drive-heavy load from its present current distortion to a target, with the IEEE 519 current limits at the point of common coupling. Basis: IEEE 519-2022 Table 2, IEC 61000-3-12.
Present spectrum, % of the fundamental (6-pulse drives with DC choke shown, editable)
Even harmonics, % of the fundamental (limited to 50 % of the 3-11 band limit for h ≤ 6)
Formula: I1 = P / (√3 · U · cos φ) · THD = √(Σ hn²) · IAHF = I1 · √(THD0² − THDt²) × margin · Isc / IL → row · Ih,even ≤ 6 ≤ 0.5 × limit3-11
Full IEEE 1584-2018 model: arcing current at full and reduced value (VarCF), enclosure size correction, incident energy at the working distance and the arc flash boundary. Range 208 V to 15 kV.
Formula: IEEE 1584-2018: Eq. 1 Iarc(0.6, 2.7, 14.3 kV) · Eq. 2 Iarc,min = Iarc (1 − 0.5 VarCF) · Eq. 3-6 E · Eq. 7-10 AFB (1.2 cal/cm²) · Eq. 11-15 CF · Eq. 16-25
Standing protective-conductor current of LED drivers and cables against the RCD rating, and how many luminaires one RCD can carry. Basis: IEC 60364-5-53, IEC 61008-1.
Formula: Ileak = N · id + (L / 100) · icable + Iother ≤ 0.3 · IΔn · Nmax = floor((0.3 · IΔn − Icable − Iother) / id)
ATS current and short-circuit rating between the utility supply and a standby generator, 3-pole or 4-pole by earthing arrangement, transition type and typical timers. Basis: IEC 60947-6-1, HD 60364-4-46:2016, IEC 60364-5-55, NFPA 110.
Formula: IB = P / (√3 · U · cos φ) · IATS ≥ max(1.25 · IB, Igen) · Igen = Sgen / (√3 · U) · Icw or Iq ≥ Ik
Minimum conductor size that survives the fault energy until the protective device clears it. Basis: IEC 60364-4-43 (434.5.2, Table 43A), IEC 60364-5-54, SBC 401.
Formula: Smin = √(I² · t) / k · tmax = (k · S / I)² · θ(t) = (θi + β) · eI²t / (K² S²) − β
Metallic screen cross-section that carries the earth fault current without overheating the insulation and sheath, plus the standing voltage of a single-point bonded run. Basis: IEC 60949 (adiabatic), IEC 60502-2.
Formula: S = I · √t / (K · √ln((θf + β) / (θi + β))) · Cu: K 226, β 234.5 · Al: K 148, β 228 · E = 2ω · 10−7 · I · ln(2s / d) (V/m, trefoil)
Current on each feed of a dual-corded (2N) rack in normal operation and after one feed is lost, against the PDU breaker continuous limit. Basis: IEC 60364-5-52 continuous loading, 2N design practice.
Formula: Irack = P / (√3 · U · cos φ) [3φ] ; P / (U · cos φ) [1φ] · Iphase,max = P · share / (ULN · cos φ) · Inormal = I / 2 · Ifailover = I ≤ 0.8 · In
Power-frequency magnetic flux density around a feeder or busbar run and the distance where it falls below a target. Basis: ICNIRP 2010 reference levels (50/60 Hz), Biot-Savart line-current model.
Formula: B = 0.2 · I / r (single) · B ≈ 0.2 · √3 · I · s / r² (flat) · B ≈ 0.2 · √1.5 · I · s / r² (trefoil) · B in µT, I in A, r and s in m · 1 µT = 10 mG
Resistance, short-time energy and relay pickup for a resistance-earthed MV system, checked against the system charging current. Basis: IEEE C57.32 (formerly IEEE 32), IEEE 142 (editions not verified). Estimate.
Formula: R = (ULL / √3) / IR · 3IC0 = 3 · ULN · 2πf · C0 · IR ≥ 3IC0 · P = ULN · IR · E = P · t
Current rating of flat copper or aluminium bars in still air at Saudi ambient, the temperature rise at your design current, AC skin effect and weight. Estimate from an empirical rating after CDA Publication 22 (formula constants, parallel-bar factors and painted uplift not verified); not a CDA or DIN 43671 rating. Temperature limits per IEC 61439-1 context.
Formula: I = 7.73 · A0.5 · p0.39 · (ΔT / 50)0.61 · kn · kmat · ksurf / √kAC · kAC = (u/2) · (sinh u + sin u) / (cosh u − cos u), u = t / δ · A [mm²], p [mm], ΔT = θmax − θamb [K], I [A]
Central battery capacity, DC circuit sizing and a lifecycle cost comparison with self-contained luminaires. Basis: EN 1838:2024 and BS 5266-1 (duration), EN 50171 (central power supply systems), EN 50172 (testing), NFPA 101 (7.9.2).
Costs: enter supplier quotes in SAR (defaults are placeholders)
Formula: Ah = N · P · t / (Udc · η) · 1.25 / krate · ΔU = 2 · I · ρ · L / A · TCO = Ccapital + nrep · Cbattery + Y · Ctest
Cold and hot tripping times of a thermal overload relay at locked-rotor current, checked against the motor starting time and safe stall time. Basis: IEC 60947-4-1 trip classes, IEC 60255-149 thermal model.
Formula: t = τ · ln[(k² − p²) / (k² − 1.15²)], k = I / Ir, p = Ipre / Ir · τ = tclass(7.2) / ln[7.2² / (7.2² − 1.15²)] · tstart = J · ω / Tacc,avg
Extra voltage the connecting leads add to the SPD protection level during a surge, compared with the equipment impulse withstand. Basis: IEC 61643-12, IEC 60364-5-53 (534), IEC 62305-4.
Formula: di/dt ≈ I / T1 (8/20: 8 µs · 10/350: 10 µs) · ΔU = L' · ℓ · di/dt · Up/f = Up + ΔU ≤ Uw · ℓmax = (Uw − Up) / (L' · di/dt)
Peak force between phase bars, bending stress against the yield strength, the longest safe support span and the force on each insulator. Basis: IEC 60865-1 (rigid conductors), IEC 61439-1 Table 7 (peak factor).
Formula: ip = κ√2 · Ik'' · F' = (μ0/2π) · (√3/2) · ip² / a · σ = VσVr · β · F' · l² / (8 · Z) ≤ q · Rp0.2, q = 1.5 · Z = b · h² / 6 · Fd = VFVr · α · F' · l
How many LED drivers one circuit can switch: combined inrush peak and energy against the contactor rating, steady current, and the driver maker's count per MCB. Basis: NEMA 410, IEC 60947-4-1, IEC 60898-1.
Formula: Rd = Û / Ipk · Ipk,tot = Û / (Rd/N + Z) · Ninrush = Rd / (Û / Ipk,cont − Z) · Nsteady = 0.8 · IAC-1 / Id · I²t = Ipk,tot² · τ / 2 · N = min(Ninrush, Nsteady, NMCB)
Building load schedule by category: connected load, demand factor, maximum demand, design current and the main breaker and transformer to request in a utility connection application. Demand factors are typical starting values, editable: replace them with the factors required by the utility or the project specification.
| Load category | Connected load (kW) | Demand factor (%) Assumed value: reference not verified |
|---|---|---|
| General lighting | ||
| Socket outlets | ||
| Air conditioning / HVAC | ||
| Water heaters | ||
| Kitchen / cooking | ||
| Motors and pumps | ||
| EV chargers | ||
| Other loads |
Formula: MD = c · Σ (Pi · DFi) · (1 + spare) · S = MD / cos φ · Ib = S / (√3 · 400 V) or S / 230 V
Installed cost against the present value of lifetime I²R losses for each standard size from the thermal minimum upward. The size with the lowest total cost is the economic size. Method: IEC 60287-3-2; resistances: IEC 60228 class 2.
Formula: CT = CI + CJ · CI = L · (A + B · S) · CJ = Imax² · R · L · Np · T · P · Q / (1 + i) · Q = Σn=1..N rn−1 · r = (1 + a)² (1 + b) / (1 + i) · T = h · μ · R = R20 [1 + α20 (θm − 20)], θm = (90 − θa) / 3 + θa
Minimum tray width from the cable cross-section and a fill limit, the next catalogue width, and the cable load against the tray safe working load at the support span. Fill basis: a project fill ratio of the usable cross-section, or NEC 392.22(A) for multiconductor cables smaller than 4/0 AWG; load basis: manufacturer SWL tested to IEC 61537.
| Group | Quantity | Overall diameter (mm) | Cable weight (kg/m) |
|---|---|---|---|
| 1 | |||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 | |||
| 6 |
Formula: A = Σ ni · π · di² / 4 · Areq = A · (1 + spare) · Wmin = Areq / (fill · depth) or NEC table area ≥ Areq · q = Σ ni · wi
Discomfort glare of a regular luminaire grid for the standard observer at mid-wall (eye 1.2 m, looking horizontally), viewed along and across the room. Basis: CIE 117, EN 12464-1.
Formula: UGR = 8 · log10[ (0.25 / Lb) · Σ Li² · ωi / pi² ] · Li = I(γ) / (A · cos γ) · ωi = A · cos γ / r² · Lb = Eind / π · ln p = (35.2 − 0.31889α − 1.22e−2α/9)·10−3β + (21 + 0.26667α − 0.002963α²)·10−5β²
Setback, spacing and the vertical illuminance profile for ground-mounted uplights in a row along a façade. Point-by-point calculation with an elliptical beam (50 % intensity at half the beam angle).
Formula: E(y) = Σ I(ψv, ψh) · d / r³ · r = √(d² + y² + x²) · I = I0 · 2−(ψv/hv)² − (ψh/hh)² · y0 = d / tan(θv/2 + tilt) · s = 2 · √(d² + (H/4)²) · tan(θh/2)
Light trespass into windows, source intensity toward the sensitive direction and upward light ratio, before and after curfew, for the environmental zone. Current reference: ILP GN01/26 (supersedes GN01/21); the zone presets are a historical table kept as editable assumed values.
Formula: Ev = I · cos θ / d² · Ipost = I · kdim · within when Ev, I and ULR are each ≤ the entered limit
Melanopic stimulus at eye level from the photopic illuminance and the melanopic ratio (M/P) of one or two LED channels, compared with the EML thresholds of WELL v2 feature L03 (historical version identified; latest version not verified). Basis: CIE S 026, WELL v2 L03.
Formula: MPmix = Σ MPi · Ei / Σ Ei · Ev,eye = ratio · Eh · EML = Ev,eye · MP · m-EDI = EML · 0.9058 (assumed) · Ev,req = EMLtarget / MP
Checks a stadium design against broadcast targets: vertical illuminance and uniformity toward the main camera, horizontal to vertical balance, colour quality, and flicker for the replay frame rate.
Formula: Flicker factor % = (Emax − Emin) / (Emax + Emin) · 100 (no phase reduction) · U1 = Emin / Emax · U2 = Emin / Eavg
How many MacAdam steps a measured or binned chromaticity sits from the target, plus its CCT and Duv from the Planckian locus. Datasets kept separate: IEC 60081 / ENERGY STAR ellipses in CIE 1931 (x, y) and the ANSI C78.377 CCT / Duv window in CIE 1960 (u, v).
Formula: n = √[(p/a)² + (q/b)²], p = Δx·cos θ + Δy·sin θ, q = −Δx·sin θ + Δy·cos θ · u' = 4x / (−2x + 12y + 3), v' = 9y / (−2x + 12y + 3) · SDCM ≈ Δu'v' / 0.0011 · Duv = ± distance to the Planckian locus in (u, v)
Classifies published TM-30 values against the Annex E design intents (Preference, Vividness, Fidelity) and flags legacy CRI gaps. Enter values from the datasheet or test report; no spectrum is computed. Basis: historical ANSI/IES TM-30-20 Annex E matrix; TM-30-24 is the identified current publication (equivalence not verified).
Rules (historical TM-30-20 Annex E; P1 and F2 confirmed, other rows not verified): P1: Rf ≥ 78, Rg ≥ 95, −1 ≤ Rcs,h1 ≤ 15 % · P2: 74, 92, −7 to 19 % · P3: 70, 89, −12 to 23 % · V1: Rg ≥ 118, Rcs,h1 ≥ 15 % · V2: 110, 6 % · V3: 100, 0 % · F1: Rf ≥ 95 · F2: Rf, Rf,h1 ≥ 90 · F3: ≥ 85
Luminaire count for a target illuminance inside the pool, with water attenuation and pool finish, plus the supply voltage and cable voltage drop. Pools and fountains are treated as separate applications; the current voltage and source-placement rules were not verified, so no compliance verdict is given.
Formula: T = e−c·p, p = √((W/2)² + (D/2)²) · Φ = E · A / (UF · MF · T) · N = ⌈Φ / Φlum⌉ · I = n · P / V · ΔV = 2 · I · ρ · L / A, ρ = 0.0225 Ω·mm²/m
Largest bollard spacing that still meets the average and minimum illuminance of the chosen pedestrian class, by point-by-point calculation over the path. Basis: EN 13201-2 P classes, CIE 115.
Formula: Eh = MF · Σ I(γ) · h / r³, r = √(d² + h²) · I(γ) = I0 · (0.75 sin6γ + 0.25/8) · cos γ · I0 = 4Φ/π (360°), 8Φ/π (180°) · smax: Ē ≥ Ēclass and Emin ≥ Emin,class
Luminaire spacing along a racking aisle for the floor and the rack-face (picking) targets, with point-by-point floor and vertical illuminance and the light wasted on rack tops. Basis: EN 12464-1.
Formula: Eh = MF · Σ I · H / r³ · Ev = MF · Σ I · (w/2) / r³ · r = √(x² + y² + z²) · I = I0 · 2−(ψacross/ha)² − (ψalong/hl)² · smax: Ēh ≥ target and Ev,min(1 m) ≥ target
Average daylight factor of a side-lit room from the glazing, its visible light transmittance, sky angle and room reflectance, compared with the EN 17037 300 lx target, plus the daylight-harvesting zones. Basis: BRE average daylight factor, EN 17037.
Formula: DF = T · Aw · θ · M / (Atot · (1 − R²)) % · θ = atan((hg/2) / overhang) − obstruction · DFtarget = 300 / Ev,d,med · 100 % · Aw,req = DFtarget · Atot · (1 − R²) / (T · θ · M)
Checks that the LED line is hidden, finds where the cove lip casts its shadow line on the ceiling, and plots the ceiling illuminance gradient from a linear source.
Formula: E(x) = (π/2) · It(φ) · hc / r², r² = x² + hc², φ = atan(x / hc) · It = I0 cosn(φ − tilt), ∫ It dφ = (lm/m) / (π/2) · shadow line xc = dlip · hc / hlip
Voltage at the far end of a constant-voltage LED strip from the copper track resistance and the feeder cable, for end, dual-end or centre feed, with the LED driver size.
Formula: Im = Pm / V · ΔVstrip = Im · Rm · L² / 2 (one end), / 8 (both ends or centre) · ΔVfeeder = 2 · I · ρ · Lc / A, ρ = 0.0225 Ω·mm²/m · Lmax = √(2 · ΔVallow / (Im · Rm)) · Pdriver ≥ 1.2 · Pm · L
Illuminance on the treads from wall-recessed step lights, the tread and riser geometry check, and the visual contrast between the nosing strip and the tread. Basis: IBC 2021 §1008.2.1 (normal power, not emergency lighting), IBC 1011.5.2, nosing contrast guidance.
Formula: E = I · cos ε / r² = I · h / r³ · ΔLRV = |LRVnosing − LRVtread| ≥ 30 · L = E · ρ / π · C = (L1 − L2) / (L1 + L2)
Annual light exposure of a displayed object against the CIE 157 limit for its light responsivity, the display time allowed, and the years to a just noticeable fade. Basis: CIE 157:2004.
Formula: H = E · hday · dyear (lx·h) · tallowed = Hlimit / E · years to JNF = HJNF / H · UV ≤ UVlimit
Screening estimate of the retinal blue light hazard of an LED luminaire from its intensity, luminous area and KB,v: the risk group at 200 mm and the threshold distance beyond which it is RG1 or lower. Basis: IEC 62471 limits, IEC TR 62778:2014 method (withdrawn); IEC 62471-7:2023 is the newer reference.
Formula: Lv = I / A · LB = Lv · KB,v · Ethr = EB,RG1 / KB,v, EB,RG1 = 1 W/m² · dthr = √(I / Ethr) · RG0 ≤ 100, RG1 ≤ 10 000, RG2 ≤ 4 000 000 W/(m²·sr)
Luminaire count with the LED lumen gain at low temperature, the LED driver cold-start check, and the emergency battery capacity lost to the cold. Basis: lumen method with manufacturer temperature data.
Formula: fT = 1 + k · (25 − T) / 100 (≤ 1.15) · Φreq = E · A / (UF · MF · fT) · N = ⌈Φreq / Φlum⌉ · trated = treq / CT
Channel duty cycles to reach a target CCT from a warm and a cool white channel, the mixed flux and power, and how far the mix sits below the Planckian locus. Basis: CIE 1931 additive mixing, McCamy CCT, Duv in CIE 1960 (u, v) against an assumed band approximating the ANSI C78.377 quadrangle.
Formula: X = x/y · Y, Z = (1 − x − y)/y · Y, Yi = Φi · di · x = ΣX / Σ(X+Y+Z) · n = (x − 0.3320)/(0.1858 − y), CCT = 449n³ + 3525n² + 6823.3n + 5520.33
Illuminance needed on a window display so it reads through the bright street scene reflected in the glass, the spotlight intensity and beam, and the effect of anti-reflective glass. Basis: veiling reflection contrast model.
Formula: Lref = ρg · Lext · Ld = E · ρd / π · CR = (τ · Ld + Lref) / Lref → E = (CR − 1) · π · Lref / (τ · ρd) · I = E · d² · θ = 2 · atan(w / 2d)
Vertical illuminance on a pedestrian facing approaching traffic from a dedicated crossing luminaire set back on the approach side, the positive contrast against the road, and the best setback. Basis: point-source vertical illuminance, road luminance per EN 13201 / CIE 115.
Formula: Ev = I · a / r³, r = √(a² + b² + Δh²), Δh = H − z · Lp = Ev · ρ / π · C = (Lp − Lbg) / Lbg · aopt = √(b² + Δh²) / √2 · Eh = I · H / r0³
Size and shape of a gobo image thrown at an angle onto a facade, the keystone stretch to pre-correct in the artwork, and the image illuminance against the ambient light on the wall. Basis: projection geometry.
Formula: h = d · cos α · x1 = h · tan(α − θ/2), x2 = h · tan(α + θ/2), L = x2 − x1 · W = 2 d · tan(θ/2) · K = cos(α − θ/2) / cos(α + θ/2) · E = Φ / (π/4 · L · W)
Night luminance of a digital billboard against the zone limit, the illuminance it puts on the nearest residential window, and the day-to-night dimming. Basis: CIE 150 environmental zones; legacy ILP PLG05 luminance table and historical CIE 150 window values as editable estimates (ILP PLG05:2023 identified, current limits not verified); authority limits are inputs.
Formula: Ewin = L · A · cos θ / d² (d ≥ 5 · max(W, H)) · dimming = Lnight / Lday · within if Lnight ≤ Llimit, Ewin ≤ Elimit
Shielding angle of a recessed LED downlight from its aperture and recess, the minimum shielding for the LED source luminance, the zone where the LED is visible, and the luminance at 65°. Basis: EN 12464-1 shielding table (secondary source).
Formula: α = atan(h / ((D + s) / 2)) · cut-off = 90° − α · LLED = Φ / (π · ALES) · rvisible = (Hc − heye) / tan α · L65 = I65 / (Aap · cos 65°)
Veiling luminance at a driver's eye from a row of road luminaires and the threshold increment TI, compared with the EN 13201-2 M-class limit as an estimate. The observer is moved over one spacing and the worst TI is kept. Basis: EN 13201-3, CIE 140.
| γ (from downward vertical) | Intensity (cd) (from the photometric file) |
|---|---|
| 70° | |
| 75° | |
| 80° | |
| 85° | |
| 90° |
Formula: Lv = k · Σ Eeye,i / θi², Eeye = I(γ) · cos θ / d² (θ [°], 1.5° ≤ θ ≤ 60°) · TI = 65 · Lv / Lav0.8 (Lav ≤ 5), TI = 95 · Lv / Lav1.05 (Lav > 5) · kage = 9.86 · [1 + (A / 66.4)4]
Vertical illuminance on a neighbour's window from the floodlights of one mast and their intensity toward the window, against the obtrusive light limits before and after curfew, with the intensity a shield must bring them down to. Basis: historical AS/NZS 4282:2019 values (superseded by AS/NZS 4282:2023) and a historical CIE 150 table, kept as editable estimates.
Formula: r = √(D² + (H − hw)²) · Ev = n · I · cos β / r², cos β = D / r · Iallowed = min(Ilimit, Elimit · r² / (n · cos β))
General lighting of a prayer hall by the lumen method, with the downlight rows following the prayer rows (saff lines) parallel to the Qibla wall, a decorative chandelier share, a mihrab accent from spotlight intensity, worshipper capacity and lighting power density.
Formula: Φ = E · A / (UF · MF) · K = L · D / (Hm · (L + D)) · N = ⌈(1 − s) · Φ / ΦDL⌉ · prow = k · drow ≤ SHR · Hm · Ev = MF · I · cos θ / d² · LPD = ΣP / A
Luminaire count and layout for an indoor (basement or multi-storey) car park or an open surface lot by the lumen method, with lighting power density and the annual energy and SEC tariff savings from occupancy sensors that dim the lighting when the area is empty.
Formula: N = ⌈E · A / (Φ · UF · MF)⌉ · K = L · W / (H · (L + W)) · s ≤ SHR · H · Ē = N · Φ · UF · MF / A · LPD = N · P / A · Eyr = P · h · 365 · (o + (1 − o) · d)
Checks one DALI line: bus supply loading, short addresses, groups and the cable voltage drop against the 2 V guidance. Basis: manufacturer guidance on IEC 62386 systems (secondary source).
Formula: Ibus = Ngear·igear + Ninput·iinput ≤ IPSU ≤ 250 mA · ΔV = I · 2·ρ·L / A ≤ 2.0 V, ρ = 0.0175 Ω·mm²/m · Lmax = 2.0·A / (2·ρ·IPSU)
Device technology: KNX TP1 (twisted pair) only, not KNX RF or KNX IP. Bus current against the segment power supply, the bus-loading rule for TP1-64 and TP1-256 devices, and the segment cable lengths. A segment is one bus section with its own supply; a line is one segment or several segments joined by line repeaters.
Formula: Iseg = Σ Ni · idev ≤ IPSU · 4M + N < 257 per segment (M = TP1-64, N = TP1-256) · Lseg ≤ 1000 m · LPSU→dev ≤ 350 m · Ldev→dev ≤ 700 m
How many LED drivers one dimmer or sensor channel can take, and the control-wire drop that shifts the dimming level at the far end. Basis: IEC 60929 Annex E (1-10 V), ANSI C137.1 (0-10 V).
Formula: Nmax = floor(Ictrl / idriver) · I = N · idriver · ΔV = I · 2·ρ·L / A · error = ΔV / 10 V · Vfar = Vmin + ΔV
Channels, universes, achievable refresh rate, RS-485 segments and Ethernet bandwidth for a dynamic architectural lighting scheme. Basis: ANSI E1.11 (DMX512-A), ANSI E1.31 (sACN), Art-Net.
Formula: nU = ⌊512 / ch⌋ · U = ⌈N / nU⌉ · tf = 92 µs + 12 µs + 44 µs·(ns + 1) · fmax = 1 / tf · BW = U · fps · Bpkt · 8
Places a ceiling photosensor relative to the window, sizes its view footprint on the workplane, and sets the calibration factor and deadband. Daylight zones per ASHRAE 90.1 sidelighting.
Formula: x = k · Hhead · D = 2 · (hceiling − hwork) · tan(θ/2) · Kcal = Etask / Esensor · Eon/off = Etask · (1 ∓ d)
Focal length needed to reach a pixel density at a distance, the field of view, and how far each pixel density reaches with the chosen lens. Thin-lens estimate; density ladders: historical DORI or the IEC 62676-4:2025 thresholds.
Formula: Wscene = Npx / ppm · f = sw · D / Wscene · HFOV = 2 · atan(sw / 2f) · Dlevel = f · Npx / (sw · ppmlevel)
Direct-field sound pressure at ear height, signal-to-noise margin at the coverage edge and the speaker grid for a room. Indicative screening: acoustic constants are editable.
Formula: SPL(r) = S1W/1m + 10·log10(P) − 20·log10(r), r = hm − he · R = r·tan(θ/2) · SPLedge = SPL(r / cos(θ/2)) − 6 dB · SNR = SPLedge − Lnoise
Estimates voice alarm intelligibility from reverberation, the direct-to-reverberant ratio and the speech-to-noise ratio with the modulation transfer function. Basis: IEC 60268-16 (simplified, single band). Indicative.
Formula: rc = 0.057·√(Q·V / T) · D/R = (rc/r)² · m(F) = |D/R + 1/(1 + j·2πF·T/13.8)| / [(1 + D/R)·(1 + 10−SNR/10)] · SNRapp = 10·log(m/(1−m)), ±15 dB · TI = (SNRapp + 15)/30 · STI = mean TI, F = 0.63 … 12.5 Hz
Link attenuation from fibre, connectors and splices against the transceiver power budget and the Ethernet application reach and channel loss entered from manufacturer data. Attenuation values are editable assumptions per fibre class and wavelength.
Formula: A = α·L + nc·ac + ns·as · B = Ptx − Srx · margin = B − A − M · Lmax = (B − nc·ac − ns·as − M) / α
Quiescent and alarm loop current, end-of-loop voltage and the control panel battery capacity. Basis: BS 5839-1:2025 Annex E or NFPA 72 secondary supply; durations from the applicable code or authority; loop limits from the panel datasheet.
Formula: Rloop = 2·ρ·L / A · Vend = V − Ia·Rloop · BS 5839-1:2025 Annex E: Cmin = 1.25·(I1·T1 + D·I2·T2), D = 1 if I2 ≤ Cmin/20, else 1.75 · NFPA 72: C = 1.25·(I1·T1 + I2·T2)
Sizes gateways for a lit road corridor of Zhaga or NEMA nodes from a radio link budget, mesh hop limits or gateway capacity, with the monthly telemetry per pole. Radio-planning estimate: the environment loss calibrates the free-space model.
Formula: FSPL = 20·log10(dkm) + 20·log10(fMHz) + 32.44 · EIRP = Pt + Gtx = ERP + 2.15 · EIRP + Grx − FSPL − Lenv − M ≥ Srx · Ngw = max(⌈Lroad / 2R⌉, ⌈N / ngw⌉) · kred · mesh: R = h · nhops
Adds up the loads on one smart pole, sizes the internal DC bus and backup battery, checks the voltage drop along a chain of poles and estimates base compartment ventilation. Indicative screening.
Formula: P = ΣPi · kdiv · 1.25 · I = P / (230·0.95) · IDC = 1.25·PDC / VDC · C = PDC·t / (V·0.8·0.9) · ΔV = (2ρs/A)·I·N(N+1)/2 · V̇ = 2.99·Q / ΔT m³/h
Picks a pixel pitch from the closest viewing distance, then gives the pixel matrix, the distance at which pixels merge for the eye, the electrical demand and the control channels. Indicative screening.
Formula: pmm ≤ dmin,m · N = ⌊W/p⌋ × ⌊H/p⌋ · dmerge = p / tan(1′) ≈ 3438·p · Pmax = N·Wpx · U = ⌈N / ⌊512/ch⌋⌉
Diameter fill ratio and a first estimate of the blowing distance from the air drag on the cable, the pusher force and duct friction, reduced for bends. Cables and ducts to the IEC 60794-5 series. Estimate only.
Formula: fill = d / D · Fair = (π/4)·d·D·Δp · f = μ·w·g · L0 = (Fair + Fpush) / f · L = L0·e−μ·Σθ
Compare 2 or 3 luminaire options over the study period: purchase, energy, maintenance and replacements, discounted to a net present value, with the break-even month. Basis: life-cycle costing (ISO 15686-5 method).
| Per luminaire | A | B | C |
|---|---|---|---|
| Unit price (SAR) | |||
| System power (W) | |||
| Rated life (×1000 h) | |||
| Maintenance (SAR/year) | |||
| Luminous flux (klm) |
Formula: NPV = N·(Cu + CL) + Σt=1..n (Et + Mt + Rt) / (1 + r)t · Et = 12·[bill(Eoth + N·P·h / 12000) − bill(Eoth)]·(1 + e)t−1 · Rt = N·(Cu + CL) at each rated-life end before the study end (Cu unit price, CL labour)
Modules per string between the cold-morning Voc ceiling and the hot-afternoon Vmp floor of the inverter MPPT window. Basis: IEC 62548 (maximum PV voltage at the lowest expected ambient), NEC 690.7(A)(1).
Formula: Voc,max = Voc·[1 + βVoc·(Tmin − 25)] · Vmp,min = Vmp·[1 + βVmp·(Tcell,hot − 25)] · Nmax = ⌊VDC,max / Voc,max⌋ · Nmin = ⌈VMPPT,min / Vmp,min⌉ · Ntrk = ⌊VMPPT,max / Vmp,cold⌋ · N = Nmin … min(Nmax, Ntrk) · Isc,max = 1.25·Isc · Tcell = Tamb + (NOCT − 20)·G/800
In an air-conditioned building the lighting power becomes heat the cooling plant must remove. This tool adds the cooling electricity to the lighting cost and shows what an LED retrofit saves at the chiller. Basis: ASHRAE Handbook, Fundamentals, ch. 18 (lighting heat gain).
Formula: Q = P·Ful·Fsa · TR = Q / 3.517 kW · Pcool = Q / COP · Ecool = Pcool·h · ΔQ = (P − PLED)·Ful·Fsa
A 400 W sodium lamp does not draw 400 W: the magnetic ballast adds its own loss, and a failed power-factor capacitor doubles the line current. This tool sets the true baseline before an LED retrofit.
Formula: Psys = Plamp + Pballast · I = Psys / (V·pf) · ΦEOL = Φ0·LLD·LOR · ΔE = (Psys − PLED)·N·h · CO₂ = ΔE·EF
Estimates the potential energy contribution of the lighting design (LPD, controls and the cooling it avoids) and on-site PV as a share of the whole-building energy. It does not award LEED or Mostadam credits: those are earned only from the official whole-building calculation for the selected rating edition and path.
Formula: ΔLPD = (LPDb − LPDd) / LPDb · Ed = LPDd·A·h·(1 − s1)(1 − s2)(1 − s3) · ΔE = (Eb − Ed)·(1 + 1/COP) · % = (ΔE + EPV) / (EUI·A)
Sizes a multi-charger site three ways: every charger at full power, a planning diversity factor, and dynamic load management (DLM) that shares the spare capacity so every vehicle still leaves charged. Smart charging is typically implemented through OCPP 2.0.1 charging profiles. Basis: IEC 60364-7-722.
Formula: Pavail = ST·pf·(1 − m) − Pbldg · Ev = Cbat·(SoCt − SoCa) / η · Preq = N·Ev / tw · checks: Ev / tw ≤ Pchg, Preq ≤ Pavail · PDLM = min(Preq, N·Pchg, Pavail) · k(N) = k∞ + (1 − k∞) / √N · Sreq = (Pbldg + PEV) / (pf·(1 − m))
Sizes a battery to hold the site demand at a target during the peak window, recharges it off-peak, and estimates the demand and energy savings with a simple payback. All prices are your inputs.
Formula: Pshave = Ppeak − Ptarget · Ereq = ∫ max(0, Pload − Ptarget) dt · Enom = Ereq / (DoD·√ηrt·SoHEOL) · Pch = Ereq / (ηrt·tch) · PCS = max(Pshave, Pch) · ΔPd = Ppk − max(Ptg, Pb + Pch) (all-hours billing) · S = DC·ΔPd·12 + (Tp − Top/ηrt)·Ereq·d · payback = CAPEX / S
PV feeds the load first while the generator never drops below its minimum load (to avoid wet stacking). Shows the PV that can be used, the curtailment, the fuel saved and the payback. No battery.
Formula: F = F0·Prated + F1·Pout (L/h) · EPV = kWp·PSH·PR · PVused = min(PV, Pload − Pmin) · Pgen = Pload − PVused ≥ Pmin · CO₂ = EFd·ΔF
Compares up to 3 transformer offers by price plus the present value of their no-load and load losses over the service life. Basis: IEC TS 60076-20 (transformer energy efficiency) and the A/B loss-capitalisation method.
| Example offers | A | B | C |
|---|---|---|---|
| Price (×1000 SAR) | |||
| P0 no-load (W) | |||
| Pk load, at rating (kW) |
Formula: TOC = Price + A·P0 + B·Pk · PVF = [(1 + i)n − 1] / [i·(1 + i)n] · A = (Ce·8760 + DC·12)·PVF · B = (Ce·8760·LLF + DC·12)·k²·PVF · LLF = 0.3·LF + 0.7·LF²
Total dynamic head from the water level, drawdown, tank lift and pipe friction, then the pump motor, the solar VFD and the PV array for a battery-free daily water target.
Formula: TDH = SWL + s + Htank + hf·(1 + km) + Hres · hf = 10.67·L·Q1.852 / (C1.852·D4.87) · Q = Qday / PSH · Eh = 0.002725·Qday·TDH · kWp = Eh / (PSH·ηp·ηm·ηVFD·PR)
Compares three supply options for an off-grid site over the project life: diesel only, PV + diesel, and PV + battery + diesel, with a day of dispatch (PV first, battery shifts the surplus, the generator covers the rest) and the levelised cost per kWh.
Formula: CRF = i·(1 + i)n / ((1 + i)n − 1) · LCOE = (Σ CAPEX·CRF + PV(replacements)·CRF + O&M + Fuel) / Eload · F = F0·Prated + F1·Pout (L/h) · RF = 1 − Egen / Eload
Velocity pressure up the shaft, drag on the pole and luminaires, base shear and overturning moment. Basis: ASCE 7-16 velocity pressure method (assumed; the edition SBC 301:2024 references is not verified).
Formula: qz = 0.613 · Kz · Kzt · Kd · V² (Pa) · Kz = 2.01 · (z/zg)2/α, z ≥ 4.6 m · Fpole = Σ qz · G · Cf · D · Δz · Flum = qz · G · EPA · n, G = 0.85 · M = Σ F · z
Embedment depth of a drilled concrete pier for a pole with no lateral restraint at grade, plus an anchor bolt tension check. Geotechnical basis (SBC 303 role): IBC 1807.3 non-constrained formula. Concrete and anchor basis (SBC 304 role): ACI 318 Chapter 17 steel strength. Both assumed equivalents, not verified against the Saudi codes.
Formula: d = 0.5 · A · [1 + √(1 + 4.36 · h / A)], A = 2.34 · P / (S1 · b), h = M / P, S1 = slat · d/3 · Tbolt = 4 · Mu / (n · Dbc) − 0.9 · W / n · Ase ≥ Tbolt / (0.75 · futa)
Internal losses plus solar gain against what the walls can shed, then the fan airflow or air conditioner size. Basis: IEC TR 60890 effective cooling surface by installation type.
Formula: A (type 1) = 1.8 · H · (W + D) + 1.4 · W · D · Qsun = α · G · (W · D + 0.5 · H · W) · Qc = Ploss + Qsun − k · A · (Ti − Ta) · Vfan = 3.1 · Qc / (Ti − Ta) m³/h · BTU/h = W × 3.412
Time to first maintenance of hot-dip galvanizing, alone or under paint (duplex), from the first-year zinc loss of the corrosivity category. Basis: ISO 9223, ISO 1461, ISO 14713-1, ISO 12944.
Formula: LHDG = tZn / rZn (rZn range of the category, ISO 9223 Table 2) · Lduplex = K · (LHDG + Lpaint)
First bending frequency of a pole with a head mass, the critical wind speed for vortex resonance and the Scruton number. Basis: EN 1991-1-4 Annex E and F, EN 40-3.
Formula: f1 = (1/2π) · √(3EI / ((Mtip + 0.236 · m · L) · L³)) · vcrit = f1 · b / St · fs = St · v / b · Sc = 2 · δs · me / (ρ · b²), ρ = 1.25 kg/m³
Rope tension, minimum breaking load and diameter, winch motor power and travel time for the raise-and-lower luminaire ring. Basis: static load with a dynamic factor and a rope working coefficient of 5.
Formula: W = (mring + nL · mL + macc) · g · Trope = W · DF / nropes · MBL ≥ Zp · T · d ≥ √(MBL / K) · P = W · DF · v / η · τ = W · DF · Ddrum / 2
Alternating colour bands for a mast or tower once day marking is required, with band height, count and paint quantity. Basis: ICAO Annex 14 Volume I Chapter 6 (Table 6-1); in Saudi Arabia the requirement is set by GACA.
Formula: w = H / n, n = 7 (H ≤ 210 m), 9, 11 ... (ICAO Table 6-1), w ≤ 30 m · area = π · (Dtop + Dbase)/2 · H · litres = area · coats / coverage
Required ventilation airflow, hydrogen release and natural vent opening for stationary batteries on charge. Basis: IEC 62485-2 (successor of EN 50272-2).
Formula: Q = 0.05 · n · Igas · Crt · 10−3 (m³/h), 0.05 = v · q · s = 24 · 0.42·10−3 · 5 · H2 = 0.42·10−3 · n · Igas · Crt · 10−3 (m³/h) · A = 28 · Q (cm²)
Backpressure of the exhaust run from the engine outlet to the stack, checked against the engine limit, with the smallest standard bore that passes. Basis: Darcy-Weisbach with hot-gas properties; limit from the engine datasheet (ISO 8528 generating sets).
Formula: ρ = 1.293 · 273 / TK · v = Q / A · 1/√f = Swamee-Jain (ε 0.046 mm) · ΔP = f · Leq / D · ρ · v² / 2 + ΔPsilencer · Leq = L + D · (n90 · k90 + n45 · k45)
Sound power from the measured or typical sound pressure level, the level at a nearby boundary, and the insertion loss of a solid wall. Basis: IEC 60076-10, manufacturer sound level table (liquid-filled, self-cooled), ISO 9613-2 barrier screening.
Formula: LWA = LpA + 10 · log(S), S = 1.25 · h · lm · Lp(r) = LWA − 10 · log(2π · r²) · Dz = 10 · log(3 + 20 · z / λ) ≤ 20 dB, λ = 343 / f, z = path difference
Protective current demand of a buried foundation, pile or anchor cage, and the sacrificial anode mass and count for the design life. Basis: ISO 15589-1 and NACE SP0169 design approach, Dwight anode resistance.
Formula: I = A · fc · i · M = Imean · t · 8760 / (u · C) · Ra = ρ / (2π · L) · [ln(8L / d) − 1] · Ia = ΔV / Ra · N = max(Ifinal / Ia, M / ma)
Horizontal seismic design force on a suspended luminaire, the sway brace cable and the slab anchor loads. Method retained: ASCE 7-16 Chapter 13 (assumed; the Saudi-adopted factors, force equation and exemptions are not verified).
Formula: Fp = 0.4 · ap · SDS · Wp · (1 + 2z/h) / (Rp / Ip), 0.3 · SDS · Ip · Wp ≤ Fp ≤ 1.6 · SDS · Ip · Wp · Fpv = 0.2 · SDS · Wp · T = Fp / cos θ · MBL ≥ SF · T
Ultimate compression and uplift from the installation torque and from individual helix bearing, with a check against a pole's overturning load on a pile group. Basis: product-specific torque factors (ICC-ES ESR-2794, AC358 criteria), individual bearing method (Perko); geotechnical basis SBC 303 role, not verified.
Formula: Qult = Kt · T · Qh = Σ Ah · (c · Nc + q' · Nq), Nq = eπ·tanφ · tan²(45° + φ/2), Nc = 9 · Qa = min(Qtorque, Qbearing) / FS · Ppile = 4M / (n · Dg) ± W / n
Checks a luminaire's Ex marking against the site: zone to EPL, gas or dust group, temperature class against the ignition temperature, and the rated ambient against Saudi site temperatures. Basis: IEC 60079-0, -10-1, -10-2, -14.
Formula: Zone 0/1/2 → EPL Ga/Gb/Gc · Zone 20/21/22 → Da/Db/Dc · IIC ⊃ IIB ⊃ IIA · gas: Tsurface < AIT (T1 450, T2 300, T3 200, T4 135, T5 100, T6 85 °C) · dust: Tmax ≤ min(⅔ Tcloud, T5mm − 75 K) · Tamax,lum ≥ Tasite
Obstacle light type, number of levels and lights, and the standby battery for a mast, pole or tower. Saudi reference: GACAR Part 139 (light intensities verified); levels and spacing follow ICAO Annex 14 Volume I, Chapter 6 as an estimate, since ICAO is not adopted without national differences. GACA decides each case through its aeronautical assessment.
Formula: H < 45 m → low intensity · 45 to 150 m → medium intensity · H > 150 m → high intensity (day) · intermediate levels when H > 45 m (medium B, C) or H > 105 m (medium A) · levels = max(2, ⌈H / s⌉), s ≤ 52 m (B, C) or 105 m (A, high) · n = ntop + (levels − 1) · nlevel · Ah = n · P · t / (V · DoD · η)
Number of TLOF and FATO perimeter lights and the floodlights for the TLOF, from the helicopter D-value and the pad geometry. Saudi reference: GACAR Part 139 (perimeter light spacing and counts verified); floodlighting and TLOF size follow ICAO Annex 14 Volume II, Chapter 5 as estimates, since ICAO is not adopted without national differences. GACA approves heliports in the Kingdom.
Formula: n = max(⌈P / smax⌉, nmin) · TLOF: smax 3 m (elevated, helideck), 5 m (surface) · nmin 14 (circular arrangement), 4 per side incl. corners (square) · FATO: 5 m, nmin 10 (circular, other shapes), 50 m + 4 per side (square) · TLOF ≥ k · D · Nflood = ⌈E · A / (Φ · UF · MF)⌉
Floodlights and high masts for a row of aircraft stands, with the aiming angle and a control tower glare check. Saudi reference: GACAR Part 139 (stand illuminance values verified); ICAO Annex 14 Volume I and the Aerodrome Design Manual Part 4 are background only, since ICAO is not adopted without national differences.
Formula: A = n · W · L · Φtotal = E · A / (UF · MF) · Nmin = ⌈Φtotal / Φlum⌉ · masts = ⌈n · W / (k · H)⌉ + 1 · Ninst = masts · ⌈Nmin / masts⌉ · Einst = Ninst · Φlum · UF · MF / A · θaim = atan(L / H) · γtower = 90° − atan((H − hcab) / d)
How much of a lane between container stacks a mast can light directly, the mast height for a target, and the floodlights and masts for the yard. Basis: lighting of outdoor work places (EN 12464-2:2024 identified, CIE 129) and simple shadow geometry.
Formula: hs = tiers · hc · s = hs · x / (H − hs) · lit = max(0, 1 − s / w) · Hreq = hs + hs · x / ((1 − f) · w) · Nmin = ⌈E · A / (Φ · UF · MF)⌉ · masts = ⌈A / (k · H)²⌉ · Ninst = masts · ⌈Nmin / masts⌉ · Einst = Ninst · Φ · UF · MF / A
Luminaire spacing and count along a platform for a target average illuminance, with a spacing-to-height check, power density, and edge and driver glare guidance. Open platforms: EN 12464-2 (2024 edition identified); enclosed stations: EN 12464-1.
Formula: s = Φ · UF · MF · rows / (E · w) · s ≤ SHR · h · Nrow = ⌈L / s⌉ · Eavg = N · Φ · UF · MF / (L · w) · LPD = N · P / (L · w)
Checks a surgical luminaire's declared photometry: central illuminance, light field ratio, irradiance per head and with overlapping heads, depth of illumination, colour rendering and CCT. Enter values from the manufacturer's IEC 60601-2-41 data sheet.
Formula: 40,000 lx ≤ Ec ≤ 160,000 lx · Ee [W/m²] = Ec [lx] · (Ee/Ec) [mW/(m²·lx)] / 1000 ≤ 700 W/m² · Ee/Ec ≤ 4.4 mW/(m²·lx) · n · Ee ≤ 700 W/m² · d50 / d10 ≥ 0.5 · 85 ≤ Ra ≤ 100 · 3000 K ≤ CCT ≤ 6700 K
Irradiance from a UV-C lamp on a surface or in a duct, the dose and exposure time for a target log reduction, and the exposure limit for people. D90 values are approximate and depend on the strain and the medium. Basis: first-order inactivation; exposure limits kept per authority: ICNIRP 2004 at 254 and 275 nm, ACGIH TLV 2022 (historical) at 222 nm.
Formula: E = n · P / (4π · r · √(r² + L²/4)) · D = log · D90 · t = D / E · S = 10−D/D90 · duct: t = Lz / v · H8h: 6 mJ/cm² (254 nm, ICNIRP 2004) → Econtinuous = H / 28,800 s ≈ 0.21 µW/cm²
Typical lighting programme for broilers or layers by age, the poultry-weighted light level (clux), the luminaires to reach the design level, and daily energy with dimming. Programme values are typical: follow the breed management guide and local rules.
Formula: clux = lux · kspectrum · N = ⌈Emax · A / (Φ · UF · MF)⌉ · dim = Eage / Emax · kWh/day = N · P · dim · hlight / 1000