Notes
1. Dimensions for H, L, W and diameter are inside wall-to-wall distance
2. API 560 requires single fired heaters with burners in floor and tubes only on sidewalls, to consider a h/w factor based on the table below

3. Vertical-tubes maximum straight length shall be 183 m (60 ft)
4. For horizontal tubes fired from both ends, the max. straight length shall be 12.2 m (40 ft)

Notes
1. The Lower Heating Value (LHV) of the fuel efficiencies shall be used for efficiency calculations
2. Typical radiation heat loss value of 1.5% is used typically considered. However, in cases with a flue gas/air preheater, a value of 2.5% is normally considered.
3. Typical Excess Air values can be used as follows:
- Natural Draft - 15% excess air
- Forced Draft - 10% excess air
4. API 560 - Pressure at the Arch should be maintained at -2.5mmH₂Og (-0.1inH₂Og)

Notes
1. Environmentally friendly body-soluble fibre is the recommended choice for fire insulation
2. HW and MW Castable is strong enough to be used on floor without a top brick layer
3. Ceramic fibre insulation are typically used in all areas except stack and ducting.
4. Ceramic fibre not suitable for convection sections with sootblowers or steam lances are used for cleaning.
5. Vapour barrier protective coating is required behind all areas lined with ceramic fibre
6. SS foil barrier is required for ceramic fibre lined areas if the sulphur content exceeds 500ppm by mass.

Notes
1. For vertical-tube, vertical-fired heaters, the maximum radiant straight tube length shall be 18,3 m (60 ft)
2. For horizontal heaters fired from both ends, the maximum radiant straight tube length shall be 12,2 m (40 ft)
3. API 560 - The tube-wall thickness should be in accordance with ISO 13704 (unless otherwise mutually agreed)
4. API 560 - Tube-wall thicknesses should include the minimum allowances for corrosion and/or erosion as follows:
- Carbon Steel Tubes - 3mm (0.125in)
- P Grade Tubes Tubes - 2mm (0.08in)
- Stainless Steel Tubes - 1mm (0.04in)
5. The unsupported length of horizontal tubes shall not exceed 35 times the outside diameter or 6 m (20 ft), whichever is less.

Notes
1. Design temp. for tube supports should be Arch temp + 100 C (180 F) 2. No credit should be considered for shielding effect of tube supports by refractory 3. API 560 states if fuel the Vanadium + Sodium content in fuel exceeds 100ppm, supports to be either: - 50Cr-50Ni metallurgy, without any coating
- Covered with 50 mm (2 in) of castable refractory (see API 560)

Notes
1. One UV scanner per burner is recommended (if total no. burners < 20)
2. One Pilot per burner is recommended
3. Electric spark ignition is recommended for each pilot
4. Forced draft system