When replacing HVAC in an existing building that has no ventilation, is it required by code to add ventilation and exhaust?
For example adding a VRF system to an old office building that currently has no ventilation and window AC units. Am I required to add ventilation and exhaust fans for...
When sizing a pump for a glycol system, I understand glycol has a pressure drop correction and well as a capacity correction as a function of the type, % volume glycol, and fluid temperature.
The question is when I give a rep the head(ft) to size a pump, do I give him the corrected pressure...
We are adding a cooling coil to an existing commercial VAV AHU without supply air duct insulation. I am trying to calculate the minimum duct temperature that is allowable while avoiding condensation forming on the duct surface. The duct is exposed in the space and some of it is in a plenum but...
We are adding a new makeup air unit to a kitchen. The existing hood and exhaust is very old.
Is it acceptable per code (IMC, IEBC) to replace the hood exhaust fan with one that matches existing airflow? The type of hood and the application it is being used for would require alot more CFM per...
I am trying to interpret the meaning of a sentence in the C403.12.1 Duct and plenum insulation and sealing section of the 2021 IECC.
"When located within a building envelope assembly, the duct or plenum shall be separated from building exterior or exempt spaces by not less than R-8 insulation...
Hello everyone.
I have some VRF heat pumps in a boiler room that contains R-410a. From my understanding of ASHRAE 15, I am ok if the boilers are direct vented. Otherwise I will need a refrigerant monitor to interlock with the boilers to prevent the open flame creating phosphene gas from burning...
I am designing a VRF system for a historic 3 story courthouse early 1900s and adding energy recovery ventilators to provide dedicated OA. The building is old and does not have life safety drawings or a fire alarm/sprinkler system. Most interior partitions is masonry.
Is a life safety analysis...
Does the continuous load factor of 125% apply to motor loads and AC equipment?
For example:
I have a panel with:
1x AC unit, using MCA and MOP on nameplate
1x 2 hp motor, using 1.25*FLC
1x combination motor (2 hp and 1 hp motor), using 1.25*FLC largest motor + FLC smaller motor
The three loads...
For offices, the requirement for OA is very small (10-30 cfm per office). I can't find in the code whether I can supply ventilation to the office using a diffuser and pull it under the door to the corridor where it is exhausted. The system is VRF with dedicated ERV providing ventilation to spaces.
How do you deal with the over-sizing of the cooling coil in Trace 700? Do you just assume the higher loads when making the selection? I am fixing cooling coil discharge temp at 55 F and Heating at 85F-90F.
With a VAV reheat system, the program forces heating cfm to always be 30% (default)or...
