RV Calculation for Fin and Tube Type Heat Exchanger

The 99 OT votes you were assessed is the height of hypocrisy demonstrated by admin!

If the hapless OP had followed your link they would have found this:

Relief Valve Manufacturer and Supplier Resources | Flow Calculator ...

www.generant.com
Generant's Flow Calculator is a useful tool for determining relief valve flow capacity. In order to protect against an overpressure condition, pressure relief valves ... Safety Relief Valve Capacity - Engineering ToolBox
www.engineeringtoolbox.com
1 inch = 25.4 mm. The relief capacity for a safety valve depends on. the relief discharge area; the compressibility factor of the actual gas; the temperature of the ... Sizing Pressure-Relief Devices - AIChE
www.aiche.org
discharge area of the relief device and diameter of the asso- ciated inlet and outlet ... relief valves are required to reach full rated capacity at 10% or less over- pressure. ... out requirements for standard pressure vessels (left) and the relief valves protecting them .... because the sizing calculations depend on the type of relief. Crosby Pressure Relief Valve Engineering Handbook
www.isibang.ac.in
understanding of relief valve sizing calculations. The user is responsible for ... set pressure, flow a rated capacity at a specified over- pressure, and close when ... Selection & Sizing of Pressure Relief Valves - PDH Online
pdhonline.com
The pressure relief valve must open at a predetermined set pressure, flow a rated .... Kp = Correction factor for relieving capacity verses. lift for relief valves in liquid ... data required to properly perform pressure relief valve sizing calculations is ... Safety Valve Sizing - Spirax Sarco
beta.spiraxsarco.com
The discharge capacity of safety valve 'A' would either be the fault load of the ... The full open capacity (KVS) of the upstream control valve, see Equation 3.21.2. Pressure Relief Valve Sizing Calculations - Critical Gas Flow Service
www.enggcyclopedia.com
Pressure Relief Valve Sizing Calculations – Critical Gas Flow Service. 3 Min Read. Share This! ... Kb : capacity correction factor due to back pressure. Kb = 1 (for ... solving pressure relief valve and piping capacity problems - Trimeric ...
trimeric.com
discovered that the pressure relief valve (PRV) capacity is inadequate. ... design interrelationships between the PRV and the inlet piping and outlet piping. ... scenario relief load, 2) identifying the largest orifice area calculated, and 3) selecting ... and other resources!

Instead the "Let Me Google That For You" king of all time gets no votes for essentially doing as you did. If one person is allowed to DOMINATE the forum and steer content and discussions as he chooses, then it is of no value, except as a Solar Eagle playground.

There is a lot of good info here, but I'm not sure how much, if any, addresses relief valves for condensers and evaporators. I worked for years with such systems, and good info was rare or sketchy. Moreover, ~1995 ASHRAE issued a revision for relief discharge piping that was ill-explained and caused a big stir in the industry. That was taken care of, but issues may still be open on items other than compressors and pressure vessels.

It would be interesting to check these references for more detail, especially if they really shed light on the subject.

i am referring ASHRAE 15 for calculation of minimum discharge capacity required for external fire safety.

Formula is C = fDL

where

C = minimum required discharge capacity of the pressure

relief device expressed as mass flow of air, lb/min (kg/s)

D = outside diameter of vessel, ft (m)

L = length of vessel, ft (m)

f = factor dependent upon type of refrigerant

it is applicable for pressure vessel and shell and tube heat exchanger but they have not mentioned for fin and tube type exchanger.

Thanks for clarifying your inquiry. Being retired, I am not necessarily up-to-date on this, but I haven't yet seen any requirements for tube/fin exchangers. Maybe they are just considered as piping, with requirements addressed in some other Code(s) than ASME or ASHRAE.

If it hasn't already been done, this could be an excellent area for original research. Up to 2015, typical practice for ammonia evaporative condensers was to have a small relief valve on each piping section, with no particular calculation involved. If the condenser is open to the to the rest of the system, other relief valves are in play. If isolated, there are a few scenarios to consider. It might take a while to describe them, so I won't do it right now, but maybe later.

thanks!

can you please let me know formula for pipe

I'm not sure there is such a formula, at least not in general use. That's why I mentioned the possibility of original research. By now, I may be guessing wrong about this.

The IMC (International Mechanical Code) has a formula for relief valves on compressors, but I don't have a copy. As far as I know, ASME has just the fDL formula for pressure vessels. For isolatable sections of pipe, that could at least be a rational start. However, that introduces the problem of many discharges into a possible header.

For relief discharge header calculations, there are formulas based on the Colebrook Formula for pipe pressure drop. The University of Wisconsin has (or used to have) a Web app for calculating pressure drops from node to node in a discharge system. IIRC, it can be found as Industrial Refrigeration Consortium.

This is a large topic, with much still to be learned (or invented).

You need to find out what are the limits of the system that feeds your heat exchanger, both thermal and mechanical, ( temp, pressure, energy), and size your relief valve to pass those flows without exceeding the mechanical limits of your equipment.

For instance, if the pressure control valve for the liquid failed full open, then your relief valve has to pass the Maximum Available Flow from the system, based on potential conditions and pipe size, flow restriction. The flow has to be high enough to keep the system pressure from exceeding the Max Working Pressure of your equipment.

With that information, now you can select and size your relief valve and piping.

Thanks!

can you pl comment on below formula? is it correct for same?

The rated discharge capacity of a rupture member or

fusible plug discharging to the atmosphere under critical flow

conditions in pounds of air per minute (kilograms of air per

second) shall be determined by the following formulas:

C = 0.64*P1*d^2

Where

C = rated discharge capacity expressed as mass flow of air,

lb/min (kg/s)

d = smallest of the internal diameter of the inlet pipe,

retaining flanges, fusible plug, and rupture member,

in. (mm)

where for rupture members,

P1 = (rated pressure psig [kPa gage] × 1.10) + 14.7 (101.33)

where for fusible plugs,

P1 = absolute saturation pressure corresponding to the

stamped temperature melting point of the fusible

plug or the critical pressure of the refrigerant used,

whichever is smaller, psia (kPa)

That formula looks good for sizing a relief valve for air, but it is unclear how it relates to your heat exchanger, as we have no idea what the two process streams are, and for which side the air is on, which of those formula variables correspond to what part of your equipment design, and what are the design Max Working Pressure limits in your construction...

...."The relief capacity for a safety valve depends on

• the relief discharge area
• the compressibility factor of the actual gas
• the temperature of the gas
• the geometry of the safety valve

A safety relief valve must be capable of relieving the capacity of the connected compressor(s) at operating pressure. Note that the relief pressure can not be set higher than the maximum rated working pressure of any equipment in the system. If the operating pressure is right below the relief pressure of the valve the valve may start leaking.

A "rule of thumb" is to set the relief pressure 10% above the working pressure of the system."...

https://www.engineeringtoolbox.com/safety-valves-capacity-d_473.html

https://www.eng-tips.com/viewthread.cfm?qid=317513

https://www.generant.com/flow-calculator/

Found this....

Sizing pressure relief devices...

https://www.aiche.org/sites/default/files/cep/20131068_r.pdf

Excellent article. On a quick scan, I didn't see any formulas specific to the OP's situation, but there was a lot of great background and general principles.