Mamus
Mechanical
- Jan 11, 2014
- 1
Hi All,
I need some form of clarification regarding pressure sending line and panel control requirements per NFPA 20 SECTION 4.30.2 and/or 40.30.6.
Background
Jockey pumps are required to have pressure indication on each pump discharge per (NFPA 20 4.30.2 &/or 4.30.6). In our existing setup, the jockey pump does not have a seperate pressure sensing line on its discharge, rather it uses the header pressure for its sequencing.
In a bid to comply with the requirements of NFPA 20 section 4.30.2 requirements we need to add a sensing line (pressure Indication) to the discharge side of our jockey pump and this means that we also need to modify the controls so that these signals from the discharge can be used to start the other firewater pumps as needed.
The existing control of the firewater system is in a single dedicated firewater panel, which operates on relays. This is vintage (i.e. original). The proposal is to put in pressure transmitters and put these signals into a PLC to start the other pumps? There are a few questions associated with this. 1) can we separate the control of the firewater pumps? This looks like the PLC sending a signal through the existing jockey pump header contact into the relay? if not, how can we modify the control of the fire water pumps?.
I need some form of clarification regarding pressure sending line and panel control requirements per NFPA 20 SECTION 4.30.2 and/or 40.30.6.
Background
Jockey pumps are required to have pressure indication on each pump discharge per (NFPA 20 4.30.2 &/or 4.30.6). In our existing setup, the jockey pump does not have a seperate pressure sensing line on its discharge, rather it uses the header pressure for its sequencing.
In a bid to comply with the requirements of NFPA 20 section 4.30.2 requirements we need to add a sensing line (pressure Indication) to the discharge side of our jockey pump and this means that we also need to modify the controls so that these signals from the discharge can be used to start the other firewater pumps as needed.
The existing control of the firewater system is in a single dedicated firewater panel, which operates on relays. This is vintage (i.e. original). The proposal is to put in pressure transmitters and put these signals into a PLC to start the other pumps? There are a few questions associated with this. 1) can we separate the control of the firewater pumps? This looks like the PLC sending a signal through the existing jockey pump header contact into the relay? if not, how can we modify the control of the fire water pumps?.