# Documentation

 Symbol Name Unit R $R_0$ Zero sequence resistance $\Omega$/m $r_1$ Radius of the circle circumscribing the three shaped conductors mm $R_1$ Resistance of conductor before emergency rating $\Omega$/m $R_{ar}$ Electrical resistance of armour $\Omega$/m $r_{arc}$ Radius of a bend m $r_b$ Equivalent radius of backfill mm $r_c$ Radius of conductor mm $R_c$ Electrical resistance of conductor $\Omega$/m $R_{c1}$ Thermal resistance, 1st loop K.m/W $R_{c2}$ Thermal resistance, 2nd loop K.m/W $R_{c20}$ DC resistance of conductor at 20°C $\Omega$/m $R_{c3}$ Thermal resistance, 3rd loop K.m/W $R_{c4}$ Thermal resistance, 4th loop K.m/W $R_{cDC}$ Electrical DC resistance of conductor $\Omega$/m $R_{CG}$ Thermal resistance of multi-layer backfill K.m/W $R_{co}$ DC resistance of conductor at 20°C $\Omega$/km $R_e$ Electrical resistance of shield and armour $\Omega$/m $R_{earth}$ Equivalent resistance of earth return path p.u. $R_{encl}$ Electrical AC resistance of enclosure $\Omega$/m $R_{encl20}$ Electrical DC resistance of enclosure at 20°C $\Omega$/m $R_{enclDC}$ Electrical DC resistance of enclosure $\Omega$/m $r_F$ Radius below the insulation mm $R_{gas}$ Specific gas constant J/kg.K $R_{gas0}$ Universal molar gas constant $r_I$ Radius of the insulation mm $r_{ij}$ Coefficient r for view factor $R_{max}$ Resistance of conductor at emergency rating $\Omega$/m $r_{mbi}$ Minimal bending radius for installation m $r_{mbif}$ Factor of minimal installation bending radius $r_{mbp}$ Minimal bending radius during cable pulling m $r_{mbpf}$ Factor of minimal pulling bending radius $r_o$ Radius of object m $R_{q11}$ Thermal resistance 11 of multi-layer backfill K.m/W $R_{q12}$ Thermal resistance 12 of multi-layer backfill K.m/W $R_{q13}$ Thermal resistance 13 of multi-layer backfill K.m/W $R_{q21}$ Thermal resistance 21 of multi-layer backfill K.m/W $R_{q22}$ Thermal resistance 22 of multi-layer backfill K.m/W $R_{q31}$ Thermal resistance 31 of multi-layer backfill K.m/W $R_{q32}$ Thermal resistance 32 of multi-layer backfill K.m/W $R_s$ Electrical resistance of shield $\Omega$/m $R_{sc}$ Electrical resistance of screen $\Omega$/m $R_{sh}$ Electrical resistance of sheath $\Omega$/m $R_{so}$ Resistance of screen and sheath at 20°C $\Omega$/m $R_{sp}$ Electrical resistance of steel pipe $\Omega$/m $r_x$ Radius to point x in insulation mm $\mathrm{Ra}_c$ Rayleigh number, conductor to gas $\mathrm{Ra}_{encl}$ Rayleigh number, gas to enclosure $\mathrm{Ra}_{gas}$ Rayleigh number gas/duct $\mathrm{Ra}_L$ Rayleigh number, ground to air $\mathrm{Ra}_{prot}$ Rayleigh number, surface to air $\mathrm{Re}_{air}$ Reynolds number for air $\mathrm{Re}_w$ Reynolds number for water $RF$ Reduction factor $\rho_4$ Thermal resistivity of soil K.m/W $\rho_{4d}$ Thermal resistivity of dry soil K.m/W $\rho_{ab}$ Thermal resistivity of armour bedding K.m/W $\rho_{ab,1}$ Thermal resistivity of 1st armour bedding K.m/W $\rho_{ab,2}$ Thermal resistivity of 2nd armour bedding K.m/W $\rho_{ar}$ Specific electrical resistivity of armour material $\Omega$.m $\rho_b$ Thermal resistivity backfill K.m/W $\rho_{b1}$ Thermal resistivity of surface layer K.m/W $\rho_{b2}$ Thermal resistivity of middle layer K.m/W $\rho_c$ Electrical resistivity of conductor material $\Omega$.m $\rho_{corr}$ Thermal resistivity of corrugation filling K.m/W $\rho_{cr}$ Thermal resistivity of conductor material K.m/W $\rho_d$ Thermal resistivity of duct material K.m/W $\rho_{d,fill}$ Thermal resistivity of bentonite filling K.m/W $\rho_{earth}$ Specific electrical resistivity of soil $\Omega$.m $\rho_{encl}$ Specific electrical resistivity of enclosure material $\Omega$.m $\rho_f$ Thermal resistivity of filler K.m/W $\rho_{gas}$ Gas density kg/m$^3$ $\rho_i$ Thermal resistivity of insulation K.m/W $\rho_j$ Thermal resistivity of jacket material K.m/W $\rho_{k2}$ Thermal resistivity of the layer located above K.m/W $\rho_{k20}$ Electrical resistivity of metallic component $\Omega$.m $\rho_{k3}$ Thermal resistivity of the layer located below K.m/W $\rho_{ki}$ Thermal resistivity of adjacent material K.m/W $\rho_{sc}$ Specific electrical resistivity of screen material $\Omega$.m $\rho_{scb}$ Thermal resistivity of screen bedding K.m/W $\rho_{scs}$ Thermal resistivity of screen serving K.m/W $\rho_{sh}$ Specific electrical resistivity of sheath material $\Omega$.m $\rho_{shj}$ Thermal resistivity of sheath jacket material K.m/W $\rho_{skid}$ Specific electrical resistivity of skid wire material $\Omega$.m $\rho_{sp}$ Specific electrical resistivity of steep pipe material $\Omega$.m $\rho_t$ Thermal resistivity of wall K.m/W