Name: NAB Pressure Reducing Valve 2" Class 150 — 4.5 BARG Set
Brand: Supreme Valves India
SKU: NAB-PRV-2IN-150-4.5B
Availability: InStock
Rating: 4.8 (127 reviews)

Question 1

What is a pressure reducing valve and how does it work?

Accepted Answer

A pressure reducing valve (PRV) is a self-operated or pilot-controlled valve that reduces a high inlet pressure to a lower, constant outlet pressure regardless of flow variations. It operates on the principle of force balance: when downstream pressure rises above the spring setpoint, the valve closes; when it drops, the valve opens. Pilot-controlled PRVs (like our NAB PRV) use a separate pilot valve that senses downstream pressure and modulates the main valve's diaphragm/spring assembly for more precise control across a wide flow range.

Question 2

What does '4.5 BARG set pressure' mean?

Accepted Answer

BARG stands for 'bar gauge' — pressure measured relative to atmospheric pressure (zero = atmospheric). 4.5 BARG means the valve is factory-set to maintain a downstream pressure of 4.5 bar above atmospheric (approximately 65 PSI gauge). The 'minimum 4.5 BARG' specification from the inquiry indicates this is the minimum set pressure required — the valve can be adjusted to higher set pressures up to the inlet pressure rating. For seawater distribution networks in marine applications, 4.5 BARG is a common working pressure for service lines.

Question 3

Why use Nickel Aluminium Bronze for a pressure reducing valve?

Accepted Answer

Nickel Aluminium Bronze (NAB, C95800) is used for pressure reducing valves in seawater and marine applications because of its exceptional corrosion resistance. NAB resists crevice corrosion, impingement attack, and biofouling in seawater at temperatures up to 80°C. For a PRV in a desalination plant or offshore platform, this means the valve body and internals will not corrode or scale, maintaining accurate pressure control over the valve's service life without frequent maintenance or replacement.

Question 4

What is the difference between a direct-acting and pilot-controlled PRV?

Accepted Answer

Direct-acting PRVs use a spring-loaded diaphragm to modulate the valve directly based on downstream pressure changes. They are simpler and lower cost but are limited to smaller sizes and lower flow capacities. Pilot-controlled (or pilot-operated) PRVs use a separate pilot valve to modulate pressure on the diaphragm of the main valve. This provides: (1) Higher flow capacity at lower pressure drop, (2) More precise downstream pressure control, (3) Better stability at varying flow rates, (4) Ability to handle large pressure differentials in a single valve. Pilot-controlled PRVs are preferred for most industrial and marine applications.

Question 5

Can the set pressure of the NAB PRV be adjusted after installation?

Accepted Answer

Yes. The NAB pressure reducing valve is adjustable within its designed range. The adjustment is made via the pilot spring adjustment screw on the pilot valve, which changes the set point from the minimum (4.5 BARG) up to the inlet pressure rating. For seawater applications where the set pressure is critical for downstream equipment protection, the adjustment range and accuracy should be confirmed with our engineering team before ordering. Typically, the factory-set pressure is specified at ordering but can be field-adjusted within ±10–15% of the set point.

Question 6

What certifications and documentation come with NAB PRVs?

Accepted Answer

Each NAB PRV ships with: EN 10204 3.1 material test certificate for the valve body (ASTM B148), EN 10204 3.1 certificate for trim materials, hydrostatic test certificate (API 598 / ISO 5208), pressure-setting report showing the factory-set downstream pressure, and dimensional inspection report. Optional certifications include: 3.2 independent witnessed inspection (Lloyd's, SGS, BV), PMI verification of material composition, UT (ultrasonic examination) of castings per ASTM B148, and NACE MR0175 / ISO 15156 compliance for H2S service.

Component	Material Specification
Body & Bonnet	Nickel Aluminum Bronze (ASTM B148 C95800)
Stem / Spindle	Monel 400 / K500
Seat / Trim	NAB / PTFE / Viton

Parameter	Specification / Standard
Manufacturing / Design Standard	API 609 / API 600 / ASME B16.34
Testing Standard	API 598 / EN 12266-1
Pressure Rating	Class 150 / Class 300 / PN16

S.N.	Parts Name	Material	Qty
1	Body	Investment Casting (ASTM A 351 Gr. CF8/CF8M)	1
2	Disc	Investment Casting (ASTM A 351 Gr. CF8/CF8M)	1
3	Spring	S.S.304 / S.S.316	1
4	Spring Washer	S.S.304 / S.S.316	1

Size	Inch	M.M.	ØD	ØD1	ØD2	L
1/2"	1/2"	15	15	38	60	16
3/4"	3/4"	20	20	47	70	20
1"	1"	25	24	55	80	22
1.1/2"	1.1/2"	40	39	75	100	32
2"	2"	50	50	93	115	40
2.1/2"	2.1/2"	65	65	109	142	46
3"	3"	80	76	127	154	50
4"	4"	100	98	148	184	60
5"	5"	125	125	177	225	69.5
6"	6"	150	150	202	230	74
8"	8"	200	201	266	333	140

2-Inch

NAB Pressure Reducing Valve — 2" Class 150 — 4.5 BARG Set

How the Pressure Reducing Valve Works

High-Pressure Inlet

Pilot Modulation

Stable Outlet Pressure

Materials of Construction (MOC)

Technical Specifications

Material of Construction

Testing Details & Standards

Dimension Tables