Hello Anti-Copy Paste Engineer,
This week an Engineer
Asked me a selection question with regards to Rising Stem Vs Non-Rising Stem.
Follow this below rule always.
- Use Non‑Rising Stem (NRS) Gate Valves for Underground installations.
- Use Rising Stem (RS) Gate Valves for above‑ground installations.
Before answering, I asked him.
"How did you come up with this rule ?"
His answer made me sweat.
"My senior told me to follow this"
Firstly, You will never be a world-class engineer
If you follow what your seniors say BLINDLY.
Secondly,
My inspiration in engineering -Elon Musk
Always say this to his SpaceX team.
“Never accept a requirement just because someone told you so.”
PS: I just love the engineering part of Elon Musk and the way he thinks from first principles that does not mean I agree with this political or any other non-engineering stuff.
By the way,
If you are not a passionate engineer,
Still you need to know the engineering logic
Behind a particular selection.
Else.
- You won’t just fail an engineering review…
- You might lose your job.
That’s exactly what happened to a fellow engineer I knew.
So let's jump into the 3 things you will learn today.
Three things you will learn today:
- When you should select Rising Vs Non-Rising Stem Gate Valves
- Engineering standards in Gate Valve
- How SpaceX saved 1.7 million by questioning requirement.
This is going to be interesting.
Let the fun begin! 😊
#1 -Engineering Learning
3D Model Failure
If you model a Rising Stem valve in 3D,
The stem physically moves upward during operation.
If you miss the vertical clearance,
- Your model clashes
- Your valve operation fails
- And your design is rejected.
This is why understanding why we choose a type of valve matters far more than “rules of thumb.”
2. How Both Designs Work
Rising Stem (RS)
- Stem moves up as the valve opens
- Visual indication of valve position
- Easy to inspect
- Needs clear vertical CLERANCE space above it.
- Better for fluids that may corrode the stem & packing.
Non‑Rising Stem (NRS)
- Stem does not move upward
- Good for underground or space‑constrained areas
- Stem is exposed to the fluid—material selection is critical
- No visual indication; requires position indicators
3. Engineering Considerations
A) Space
- Above-ground + space available → RS valve
- Above-ground + no vertical clearance → NRS valve
- Underground → NRS valve
B) Fluid Properties
- Corrosive fluid → Prefer RS
(because the stem is not in contact with the medium)
- Non-corrosive fluid → NRS acceptable
C) Operational Considerations
- RS is easier to maintain
- RS gives clear position visibility
- NRS saves space but increases inspection complexity
Valve Selection Algorithm (Simple & Logical)
Ask yourself, the following Questions
Q) Is the valve underground?
Yes → Use Non-Rising Stem Gate valve (With below check)
Check : Stem material must resist fluid corrosion
If the Answer is No.
And you have Above Ground Installation.
Q) Is there vertical space available?
Yes → Use Rising Stem Gate valve.
And if you have No vertical space (in Above Ground Installation).
Q) Check fluid: Is fluid corrosive?
Yes → Then check if you can re-design the layout.
And then use Rising Stem Gate Valve.
And if you have No vertical space (Even after re-design of layout).
Use Non-Rising Stem valve (But the Stem will be in contact with Fluid hence the material must be compatible as per the fluid).
Want to learn control valves in depth.
We will be having a Live Cohort on Control Valves.
ACV - 2026 will soon be opening doors on June 1st.
It called "Advanced Control Valve Cohort"
#2- Engineering Standard
The Big Players: API vs. ASME
Most engineers get these confused.
Think of it this way:
ASME is the "How to Build" guide.
API is the "Refinery Toughened" guide.
1. ASME B16.34: The Foundation
This is the mother of standards.
It dictates the Pressure-Temperature ratings.
➜ Covers Wall Thickness.
➜ Defines Body Material limits.
➜ The "Base Layer" for safety.
2. API 600: The Heavyweight
Used for Steel Gate Valves. Common in Oil & Gas.
- ➜ Focuses on Heavy Duty builds.
- ➜ Specifics on Bolted Bonnets.
- ➜ Defines the "Stellite" hard-facing.
3. API 602: The Compact Warrior
This is for the small stuff. Usually 4 inches and below.
- ➜ Forged Steel construction.
- ➜ Ideal for high-pressure drains.
- ➜ Compact, rugged design.
4. Water Industry Standard: The AWWA Standard
If you are moving water, API is overkill (and expensive).
You look to AWWA.
AWWA C509 / C515
These govern Resilient-Seated valves.
- C509: Cast Iron (Thicker).
- C515: Ductile Iron (Lighter/Stronger).
- Used for potable water systems.
#3 -Career Tip
During SpaceX Rocket preparation
NASA had a $2 million requirement
For the lifting cranes required to move rockets .
Nobody questioned it.
Elon said " Why is the cost (rent) of lifting cranes 2 Million.
They said "NASA / military said no"
He questioned the requirement.
And , the cost dropped to $200k.
Most requirements we outdated (but nobody questioned them)
10× reduction.
Oil & gas has the same problem.
Some requirements have been blindly repeated for 100+ years.
Be bold.
Ask why.
Elon Musk puts it bluntly:
“All requirements are inherently dumb.
Your job is to question them and make them less dumb.”
#4 - How I can help
ACV Cohort Philosophy
In the ACV cohort,
We ask questions—because that’s how knowledge sticks.
- You think
- You reason
- And You become confident.
If you'd like the program details or want to join the waitlist, you can check them out here
You can join the Advanced Control Valve list below.
#5 - Rate Today's lesson
How was todays email lesson?
Until next week,
Happy Learning and Keep Smiling.
Asad Shaikh
Your super passionate Control Valve Friend!!
See you next week!
www.Asad-Shaikh.com
